This is based on a patch by Nicolas Iooss. He writes:
When secilc compiles the following policy:
(block b1
(optional o1
(blockinherit b1)
(blockinherit x)
)
)
it disables the optional block at pass 3 (CIL_PASS_BLKIN_LINK)
because the block "x" does not exist.
__cil_resolve_ast_last_child_helper() calls
cil_tree_children_destroy() on the optional block, which destroys
the two blockinherit statements. But the (blockinherit b1) node
was referenced inside (block b1) node, in its block->bi_nodes list.
Therefore, when this list is used at pass 4 (CIL_PASS_BLKIN_COPY),
it contains a node which was freed: this triggers a use-after-free
issue
Fix this issue by removing blockinherit nodes from their lists of
nodes block->bi_nodes when they are being destroyed. As
cil_destroy_blockinherit() does not have a reference to the node
containing the blockinherit data, implement this new logic in
cil_tree_node_destroy().
This issue was found while investigating a testcase from an OSS-Fuzz
issue which seems unrelated (a Null-dereference READ in
cil_symtab_get_datum,
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=29861).
Reported-by: Nicolas Iooss <nicolas.iooss@m4x.org>
Signed-off-by: James Carter <jwcart2@gmail.com>
Acked-by: Nicolas Iooss <nicolas.iooss@m4x.org>
The following CIL policy triggers a heap use-after-free in secilc
because when the blockinherit node is destroyed, the block node was
already destroyed:
(block b2a)
(blockinherit b2a)
Fix this by setting blockinherit->block to NULL when destroying block.
Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
Acked-by: James Carter <jwcart2@gmail.com>
When __cil_validate_constrain_expr() fails,
cil_constrain_to_policydb_helper() does not destroy the constraint
expression. This leads to a memory leak reported by OSS-Fuzz with the
following CIL policy:
(class CLASS (PERM))
(classorder (CLASS))
(sid SID)
(sidorder (SID))
(user USER)
(role ROLE)
(type TYPE)
(category CAT)
(categoryorder (CAT))
(sensitivity SENS)
(sensitivityorder (SENS))
(sensitivitycategory SENS (CAT))
(allow TYPE self (CLASS (PERM)))
(roletype ROLE TYPE)
(userrole USER ROLE)
(userlevel USER (SENS))
(userrange USER ((SENS)(SENS (CAT))))
(sidcontext SID (USER ROLE TYPE ((SENS)(SENS))))
(constrain
(CLASS (PERM))
(or
(eq t1 TYPE)
(or
(eq t1 TYPE)
(or
(eq t1 TYPE)
(or
(eq t1 TYPE)
(or
(eq t1 TYPE)
(eq t1 TYPE)
)
)
)
)
)
)
Add constraint_expr_destroy(sepol_expr) to destroy the expression.
Moreover constraint_expr_destroy() was not freeing all items of an
expression. Code in libsepol/src and checkpolicy contained while loop to
free all the items of a constraint expression, but not the one in
libsepol/cil. As freeing only the first item of an expression is
misleading, change the semantic of constraint_expr_destroy() to iterate
the list of constraint_expr_t and to free all items.
Fixes: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=28938
Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
Acked-by: James Carter <jwcart2@gmail.com>
Nicolas Iooss reports:
A few weeks ago, OSS-Fuzz got configured in order to fuzz the CIL
policy compiler (cf.
https://github.com/SELinuxProject/selinux/issues/215 and
https://github.com/google/oss-fuzz/pull/4790). It reported a bunch of
simple issues, for which I will submit patches. There are also more
subtle bugs, like the one triggered by this CIL policy:
(class CLASS (PERM))
(classorder (CLASS))
(sid SID)
(sidorder (SID))
(sensitivity SENS)
(sensitivityorder (SENS))
(type TYPE)
(allow TYPE self (CLASS (PERM)))
(block b
(optional o
(sensitivitycategory SENS (C)) ; Non-existing category
triggers disabling the optional
(common COMMON (PERM1))
(classcommon CLASS COMMON)
(allow TYPE self (CLASS (PERM1)))
)
)
On my computer, secilc manages to build this policy fine, but when
clang's Address Sanitizer is enabled, running secilc leads to the
following report:
$ make -C libsepol/src CC=clang CFLAGS='-g -fsanitize=address' libsepol.a
$ clang -g -fsanitize=address secilc/secilc.c libsepol/src/libsepol.a
-o my_secilc
$ ./my_secilc -vv testcase.cil
Parsing testcase.cil
Building AST from Parse Tree
Destroying Parse Tree
Resolving AST
Failed to resolve sensitivitycategory statement at testcase.cil:12
Disabling optional 'o' at testcase.cil:11
Resetting declarations
=================================================================
==181743==ERROR: AddressSanitizer: heap-use-after-free on address
0x6070000000c0 at pc 0x55ff7e445d24 bp 0x7ffe7eecfba0 sp
0x7ffe7eecfb98
READ of size 4 at 0x6070000000c0 thread T0
#0 0x55ff7e445d23 in __class_reset_perm_values
/git/selinux-userspace/libsepol/src/../cil/src/cil_reset_ast.c:17:17
The problem is that the optional branch is destroyed when it is disabled,
so the common has already been destroyed when the reset code tries to
access the number of common permissions, so that it can change the
value of the class permissions back to their original values.
The solution is to count the number of class permissions and then
calculate the number of common permissions.
Reported-by: Nicolas Iooss <nicolas.iooss@m4x.org>
Signed-off-by: James Carter <jwcart2@gmail.com>
This field is suppose to be used to track the number of primary names in
the symtab. It was not being updated or used.
Increment the nprim field when a new datum is added to the symtab and
decrement the field when a datum is removed.
Signed-off-by: James Carter <jwcart2@gmail.com>
OSS-Fuzz found a direct memory leak in policydb_filetrans_insert()
because filenametr_destroy() does not fully destroy the list associated
with a typetransition.
More precisely, let's consider this (minimized) CIL policy:
(class CLASS (PERM))
(classorder (CLASS))
(sid SID)
(sidorder (SID))
(user USER)
(role ROLE)
(type TYPE) ; "type 1" in libsepol internal structures
(type TYPE2) ; "type 2" in libsepol internal structures
(type TYPE3) ; "type 3" in libsepol internal structures
(category CAT)
(categoryorder (CAT))
(sensitivity SENS)
(sensitivityorder (SENS))
(sensitivitycategory SENS (CAT))
(allow TYPE self (CLASS (PERM)))
(roletype ROLE TYPE)
(userrole USER ROLE)
(userlevel USER (SENS))
(userrange USER ((SENS)(SENS (CAT))))
(sidcontext SID (USER ROLE TYPE ((SENS)(SENS))))
(typetransition TYPE2 TYPE CLASS "some_file" TYPE2)
(typetransition TYPE3 TYPE CLASS "some_file" TYPE3)
The two typetransition statements make policydb_filetrans_insert()
insert an item with key {ttype=1, tclass=1, name="some_file"} in the
hashmap p->filename_trans. This item contains a linked list of two
filename_trans_datum_t elements:
* The first one uses {otype=2, stypes=bitmap containing 2}
* The second one uses {otype=3, stypes=bitmap containing 3}
Nevertheless filenametr_destroy() (called by
hashtab_map(p->filename_trans, filenametr_destroy, NULL);) only frees
the first element. Fix this memory leak by freeing all elements.
This issue was introduced by commit 42ae834a74 ("libsepol,checkpolicy:
optimize storage of filename transitions") and was never present in the
kernel, as filenametr_destroy() was modified appropriately in commit
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c3a276111ea2572399281988b3129683e2a6b60b
Fixes: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=29138
Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
Acked-by: Ondrej Mosnacek <omosnace@redhat.com>
OSS-Fuzz found a NULL pointer dereference when the CIL compiler tries to
compile a policy with an invalid integer:
$ echo '(ioportcon(2())n)' > tmp.cil
$ secilc tmp.cil
Segmentation fault (core dumped)
This is because strtol() is called with a NULL pointer, in
cil_fill_integer().
Fix this by checking that int_node->data is not NULL. While at it, use
strtoul() instead of strtol() to parse an unsigned integer.
When using "val > UINT32_MAX" with "unsigned long val;", it is expected
that some compilers emit a warning when the size of "unsigned long" is
32 bits. In theory gcc could be such a compiler (with warning
-Wtype-limits, which is included in -Wextra). Nevertheless this is
currently broken, according to
https://gcc.gnu.org/pipermail/gcc-help/2021-January/139755.html and
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89126 (this bug was
opened in January 2019).
In order to prevent this warning from appearing, introduce some
preprocessor macros around the bound check.
Fixes: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=28456
Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
Acked-by: James Carter <jwcart2@gmail.com>
When __cil_resolve_perms fails, it does not destroy perm_datums, which
leads to a memory leak reported by OSS-Fuzz with the following CIL
policy:
(class cl01())
(classorder(cl01))
(type at02)
(type tpr3)
(allow at02 tpr3(cl01((s))))
Calling cil_list_destroy() fixes the issue.
Fixes: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=28466
Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
OSS-Fuzz found a heap buffer overflow (out-of-bound reads) when the CIL
compiler tries to report a recursive blockinherit with an optional
block:
$ echo '(block b (optional o (blockinherit b)))' > tmp.cil
$ secilc tmp.cil
Segmentation fault (core dumped)
This is because cil_print_recursive_blockinherit() assumes that all
nodes are either CIL_BLOCK or CIL_BLOCKINHERIT. Add support for other
block kinds, using cil_node_to_string() to show them.
Fixes: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=28462
Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
Function cil_add_file() copies its input into a newly-allocated buffer,
and does not modify "name". State these properties in the types of
parameters by adding "const" qualifiers.
This enables using LibFuzzer directly on cil_add_file(), without a
warning about discarding "const" qualifier:
fuzz-secilc.c: In function ‘LLVMFuzzerTestOneInput’:
fuzz-secilc.c:57:31: warning: passing argument 3 of ‘cil_add_file’
discards ‘const’ qualifier from pointer target type
[-Wdiscarded-qualifiers]
57 | if (cil_add_file(db, "fuzz", data, size) != SEPOL_OK)
| ^~~~
In file included from fuzz-secilc.c:26:
/usr/include/sepol/cil/cil.h:45:57: note: expected ‘char *’ but
argument is of type ‘const uint8_t *’ {aka ‘const unsigned char *’}
45 | extern int cil_add_file(cil_db_t *db, char *name, char *data, size_t size);
| ~~~~~~^~~~
Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
OSS-Fuzz found a Null-dereference READ in the CIL compiler when trying
to compile the following policy:
(optional o (validatetrans x (eq t3 (a ()))))
With some logs, secilc reports:
Invalid syntax
Destroying Parse Tree
Resolving AST
Failed to resolve validatetrans statement at fuzz:1
Disabling optional 'o' at tmp.cil:1
So there is an "Invalid syntax" error, but the compilation continues.
Fix this issue by stopping the compilation when cil_fill_list() reports
an error:
Invalid syntax
Bad expression tree for constraint
Bad validatetrans declaration at tmp.cil:1
Fixes: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=29061
Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
OSS-Fuzz found a heap use-after-free when the CIL compiler destroys its
database after failing to compile the following policy:
(validatetrans x (eq t3 (a)))
This is caused by the fact that the validatetrans AST object references
a stack variable local to __cil_fill_constraint_leaf_expr, when parsing
the list "(a)":
struct cil_list *sub_list;
cil_fill_list(current->next->next->cl_head, leaf_expr_flavor, &sub_list);
cil_list_append(*leaf_expr, CIL_LIST, &sub_list);
Drop the & sign to really add the list like it is supposed to be.
Fixes: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=28507
Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
OSS-Fuzz found a NULL pointer dereference when the CIL compiler tries to
compile a policy where a categoryalias references an unused
categoryalias:
$ echo '(categoryalias c0)(categoryalias c1)(categoryaliasactual c0 c1)' > tmp.cil
$ secil tmp.cil
Segmentation fault (core dumped)
In such a case, a1 can become NULL in cil_resolve_alias_to_actual().
Add a check to report an error when this occurs. Now the error message
is:
Alias c0 references an unused alias c1 at tmp.cil:1
Fixes: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=28471
Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
cil_copy_expandtypeattribute prints "cil_copy_expandtypeattribute 656"
which is quite annoying. Remove the fprintf statement responsible for
this.
While at it, remove another one in cil_tree_print_node()
Fixes: https://lore.kernel.org/selinux/3c2ab876-b0b7-42eb-573d-e5b450a7125a@gmail.com/T/#u
Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
It was found in https://github.com/google/oss-fuzz/pull/4790:
```
Invalid token '' at line 2 of fuzz
NEW_FUNC[1/2]: 0x67fff0 in yy_get_previous_state /src/selinux/libsepol/src/../cil/src/cil_lexer.c:1143
NEW_FUNC[2/2]: 0x6803e0 in yy_try_NUL_trans /src/selinux/libsepol/src/../cil/src/cil_lexer.c:1176
=================================================================
==12==ERROR: AddressSanitizer: heap-use-after-free on address 0x602000007992 at pc 0x000000681800 bp 0x7ffccddee530 sp 0x7ffccddee528
WRITE of size 1 at 0x602000007992 thread T0
SCARINESS: 41 (1-byte-write-heap-use-after-free)
#0 0x6817ff in cil_yy_switch_to_buffer /src/selinux/libsepol/src/../cil/src/cil_lexer.c:1315:17
#1 0x6820cc in cil_yy_scan_buffer /src/selinux/libsepol/src/../cil/src/cil_lexer.c:1571:2
#2 0x682662 in cil_lexer_setup /src/selinux/libsepol/src/../cil/src/cil_lexer.l:73:6
#3 0x5cf2ae in cil_parser /src/selinux/libsepol/src/../cil/src/cil_parser.c:220:2
#4 0x56d5e2 in cil_add_file /src/selinux/libsepol/src/../cil/src/cil.c:514:7
#5 0x556e91 in LLVMFuzzerTestOneInput /src/secilc-fuzzer.c:434:7
#6 0x459ab1 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:599:15
#7 0x45a755 in fuzzer::Fuzzer::TryDetectingAMemoryLeak(unsigned char const*, unsigned long, bool) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:675:3
#8 0x45acd9 in fuzzer::Fuzzer::MutateAndTestOne() /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:747:5
#9 0x45b875 in fuzzer::Fuzzer::Loop(std::__Fuzzer::vector<fuzzer::SizedFile, fuzzer::fuzzer_allocator<fuzzer::SizedFile> >&) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:883:5
#10 0x4499fb in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerDriver.cpp:906:6
#11 0x473a32 in main /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerMain.cpp:20:10
#12 0x7f982296d83f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2083f)
#13 0x41e758 in _start (/out/secilc-fuzzer+0x41e758)
DEDUP_TOKEN: cil_yy_switch_to_buffer--cil_yy_scan_buffer--cil_lexer_setup
0x602000007992 is located 2 bytes inside of 4-byte region [0x602000007990,0x602000007994)
freed by thread T0 here:
#0 0x521ef2 in free /src/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:127:3
#1 0x56d630 in cil_add_file /src/selinux/libsepol/src/../cil/src/cil.c:526:2
#2 0x556e91 in LLVMFuzzerTestOneInput /src/secilc-fuzzer.c:434:7
#3 0x459ab1 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:599:15
#4 0x458fba in fuzzer::Fuzzer::RunOne(unsigned char const*, unsigned long, bool, fuzzer::InputInfo*, bool, bool*) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:505:3
#5 0x45acc7 in fuzzer::Fuzzer::MutateAndTestOne() /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:745:19
#6 0x45b875 in fuzzer::Fuzzer::Loop(std::__Fuzzer::vector<fuzzer::SizedFile, fuzzer::fuzzer_allocator<fuzzer::SizedFile> >&) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:883:5
#7 0x4499fb in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerDriver.cpp:906:6
#8 0x473a32 in main /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerMain.cpp:20:10
#9 0x7f982296d83f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2083f)
DEDUP_TOKEN: free--cil_add_file--LLVMFuzzerTestOneInput
previously allocated by thread T0 here:
#0 0x52215d in malloc /src/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3
#1 0x5cecb8 in cil_malloc /src/selinux/libsepol/src/../cil/src/cil_mem.c:39:14
#2 0x56d584 in cil_add_file /src/selinux/libsepol/src/../cil/src/cil.c:510:11
#3 0x556e91 in LLVMFuzzerTestOneInput /src/secilc-fuzzer.c:434:7
#4 0x459ab1 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:599:15
#5 0x458fba in fuzzer::Fuzzer::RunOne(unsigned char const*, unsigned long, bool, fuzzer::InputInfo*, bool, bool*) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:505:3
#6 0x45acc7 in fuzzer::Fuzzer::MutateAndTestOne() /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:745:19
#7 0x45b875 in fuzzer::Fuzzer::Loop(std::__Fuzzer::vector<fuzzer::SizedFile, fuzzer::fuzzer_allocator<fuzzer::SizedFile> >&) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:883:5
#8 0x4499fb in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerDriver.cpp:906:6
#9 0x473a32 in main /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerMain.cpp:20:10
#10 0x7f982296d83f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2083f)
DEDUP_TOKEN: malloc--cil_malloc--cil_add_file
SUMMARY: AddressSanitizer: heap-use-after-free /src/selinux/libsepol/src/../cil/src/cil_lexer.c:1315:17 in cil_yy_switch_to_buffer
Shadow bytes around the buggy address:
0x0c047fff8ee0: fa fa fd fa fa fa fd fd fa fa fd fa fa fa fd fd
0x0c047fff8ef0: fa fa fd fa fa fa fd fd fa fa fd fa fa fa fd fd
0x0c047fff8f00: fa fa fd fa fa fa fd fa fa fa fd fa fa fa fd fd
0x0c047fff8f10: fa fa fd fa fa fa fd fd fa fa fd fa fa fa fd fd
0x0c047fff8f20: fa fa fd fa fa fa fd fd fa fa fd fa fa fa fd fa
=>0x0c047fff8f30: fa fa[fd]fa fa fa fd fa fa fa fd fa fa fa fd fa
0x0c047fff8f40: fa fa fd fa fa fa fd fa fa fa fd fa fa fa fd fa
0x0c047fff8f50: fa fa fd fa fa fa fd fd fa fa fd fa fa fa fd fa
0x0c047fff8f60: fa fa fd fd fa fa fd fa fa fa fd fd fa fa fd fa
0x0c047fff8f70: fa fa 00 00 fa fa 02 fa fa fa 02 fa fa fa 00 fa
0x0c047fff8f80: fa fa 03 fa fa fa 00 fa fa fa 03 fa fa fa 00 fa
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
Shadow gap: cc
==12==ABORTING
```
Signed-off-by: Evgeny Vereshchagin <evvers@ya.ru>
Acked-by: Nicolas Iooss <nicolas.iooss@m4x.org>
In cil_symtab.h, the macro FLAVOR() is defined. It refers to the
flavor of the first node in the list of nodes that declare the datum.
(The flavors of every node should be the same.) While the macro was
used in many places, it was not used everywhere that it could be.
Change all the remaining places to use FLAVOR().
Signed-off-by: James Carter <jwcart2@gmail.com>
In cil_symtab.h, the macro NODE() is defined. It refers to the first
node in the list of nodes that declare that datum. (It is rare for
a datum to have more than one node in this list.) While the macro was
used in many places, it was not used everywhere that it could be.
Change all the remaining places to use NODE().
Signed-off-by: James Carter <jwcart2@gmail.com>
Block, macro, and optional names are all in stored in a block symtab. A
declarations fully-qualified name includes all of the block names from
the root node to the declaration separated by dots. Macro and optional
names are only used when trying to determine the block referred to by
an "in" block. An optional block name might be stored in a macro's
symtab, but optional blocks have no symtab and (*datum)->symtab just
refers to the symtab of the datum which would be the current symtab.
Since the assignment is not needed, remove it so the code is clearer.
Signed-off-by: James Carter <jwcart2@gmail.com>
When resolving names, the struct cil_args_resolve is passed to the
various resolve functions. The field last_resolved_name is not used.
Remove the last_resolved_name field from struct cil_args_resolve.
Signed-off-by: James Carter <jwcart2@gmail.com>
Since cil_gen_node() is only called from declarations, the check to
determine if the node is a declaration is not needed, so remove it.
Signed-off-by: James Carter <jwcart2@gmail.com>
The function cil_tree_walk() has an argument that can be used by
the process_node helper function to tell cil_tree_walk() to skip
the node's sub-tree or the rest of the current branch. The constants
CIL_TREE_SKIP_NOTHING, CIL_TREE_SKIP_NEXT and CIL_TREE_SKIP_HEAD are
defined to be used by that argument.
Fixed two instances in the function __cil_build_ast_node_helper()
where the value 1 is used instead of the more informative
CIL_TREE_SKIP_NEXT.
Signed-off-by: James Carter <jwcart2@gmail.com>
In get_class_info(), if realloc(class_buf, new_class_buf_len) fails to
grow the memory, the function returns NULL without freeing class_buf.
This leads to a memory leak which is reported by clang's static
analyzer:
https://580-118970575-gh.circle-artifacts.com/0/output-scan-build/2020-11-11-194150-6152-1/report-42a899.html#EndPath
Fix the memory leak by calling free(class_buf).
While at it, use size_t insted of int to store the size of the buffer
which is growing.
Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
Both tunableif and booleanif use conditional blocks (either true or
false). No ordering is imposed, so a false block can be first (or even
the only) block. Checks are made to ensure that the first and second
(if it exists) blocks are either true or false, but no checks are made
to ensure that there is only one true and/or one false block. If there
are more than one true or false block, only the first will be used and
the other will be ignored.
Create a function, cil_verify_conditional_blocks(), that gives an error
along with a message if more than one true or false block is specified
and call that function when building tunableif and booleanif blocks in
the AST.
Signed-off-by: James Carter <jwcart2@gmail.com>
Acked-by: Ondrej Mosnacek <omosnace@redhat.com>
Previous commits removed some symbols and broke ABI, therefore we need to change
SONAME.
See the following quotes from distribution guidelines:
https://www.debian.org/doc/debian-policy/ch-sharedlibs.html#run-time-shared-libraries
Every time the shared library ABI changes in a way that may break
binaries linked against older versions of the shared library, the SONAME
of the library and the corresponding name for the binary package
containing the runtime shared library should change.
https://docs.fedoraproject.org/en-US/packaging-guidelines/#_downstream_so_name_versioning
When new versions of the library are released, you should use an ABI
comparison tool to check for ABI differences in the built shared
libraries. If it detects any incompatibilities, bump the n number by
one.
Signed-off-by: Petr Lautrbach <plautrba@redhat.com>
These functions were converted to no-op by commit
c3f9492d7f ("selinux: Remove legacy local boolean and user code") and
left in libsepol/src/deprecated_functions.c to preserve API/ABI. As we
change libsepol ABI dropping duplicate symbols it's time to drop these
functions too.
Signed-off-by: Petr Lautrbach <plautrba@redhat.com>
Versioned duplicate symbols cause problems for LTO. These symbols were
introduced during the CIL integration several releases ago and were only
consumed by other SELinux userspace components.
Fixes: https://github.com/SELinuxProject/selinux/issues/245
Signed-off-by: Petr Lautrbach <plautrba@redhat.com>
When find_avtab_node() is called with key->specified & AVTAB_XPERMS and
xperms=NULL, xperms is being dereferenced. This is detected as a
"NULL pointer dereference issue" by static analyzers.
Even though it does not make much sense to call find_avtab_node() in a
way which triggers the NULL pointer dereference issue, static analyzers
have a hard time with calls such as:
node = find_avtab_node(handle, avtab, &avkey, cond, NULL);
... where xperms=NULL.
So, make the function report an error instead of crashing.
Here is an example of report from clang's static analyzer:
https://558-118970575-gh.circle-artifacts.com/0/output-scan-build/2020-10-02-065849-6375-1/report-d86a57.html#EndPath
Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
Contrary to Linux kernel, BUG_ON() does not halt the execution, in
libsepol/src/services.c. Instead it displays an error message and
continues the execution.
This means that this code does not prevent an out-of-bound write from
happening:
case CEXPR_AND:
BUG_ON(sp < 1);
sp--;
s[sp] &= s[sp + 1];
Use if(...){BUG();rc=-EINVAL;goto out;} constructions instead, to make
sure that the array access is always in-bound.
This issue has been found using clang's static analyzer:
https://558-118970575-gh.circle-artifacts.com/0/output-scan-build/2020-10-02-065849-6375-1/report-50a861.html#EndPath
Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
When compiling SELinux userspace tools with -ftrapv (this option
generates traps for signed overflow on addition, subtraction,
multiplication operations, instead of silently wrapping around),
semodule crashes when running the tests from
scripts/ci/fedora-test-runner.sh in a Fedora 32 virtual machine:
[root@localhost selinux-testsuite]# make test
make -C policy load
make[1]: Entering directory '/root/selinux-testsuite/policy'
# Test for "expand-check = 0" in /etc/selinux/semanage.conf
# General policy build
make[2]: Entering directory '/root/selinux-testsuite/policy/test_policy'
Compiling targeted test_policy module
Creating targeted test_policy.pp policy package
rm tmp/test_policy.mod.fc
make[2]: Leaving directory '/root/selinux-testsuite/policy/test_policy'
# General policy load
domain_fd_use --> off
/usr/sbin/semodule -i test_policy/test_policy.pp test_mlsconstrain.cil test_overlay_defaultrange.cil test_add_levels.cil test_glblub.cil
make[1]: *** [Makefile:174: load] Aborted (core dumped)
Using "coredumpctl gdb" leads to the following strack trace:
(gdb) bt
#0 0x00007f608fe4fa25 in raise () from /lib64/libc.so.6
#1 0x00007f608fe38895 in abort () from /lib64/libc.so.6
#2 0x00007f6090028aca in __addvsi3.cold () from /lib64/libsepol.so.1
#3 0x00007f6090096f59 in __avrule_xperm_setrangebits (low=30, high=30, xperms=0x8b9eea0)
at ../cil/src/cil_binary.c:1551
#4 0x00007f60900970dd in __cil_permx_bitmap_to_sepol_xperms_list (xperms=0xb650a30, xperms_list=0x7ffce2653b18)
at ../cil/src/cil_binary.c:1596
#5 0x00007f6090097286 in __cil_avrulex_ioctl_to_policydb (k=0xb8ec200 "@\023\214\022\006", datum=0xb650a30,
args=0x239a640) at ../cil/src/cil_binary.c:1649
#6 0x00007f609003f1e5 in hashtab_map (h=0x41f8710, apply=0x7f60900971da <__cil_avrulex_ioctl_to_policydb>,
args=0x239a640) at hashtab.c:234
#7 0x00007f609009ea19 in cil_binary_create_allocated_pdb (db=0x2394f10, policydb=0x239a640)
at ../cil/src/cil_binary.c:4969
#8 0x00007f609009d19d in cil_binary_create (db=0x2394f10, policydb=0x7ffce2653d30) at ../cil/src/cil_binary.c:4329
#9 0x00007f609008ec23 in cil_build_policydb_create_pdb (db=0x2394f10, sepol_db=0x7ffce2653d30)
at ../cil/src/cil.c:631
#10 0x00007f608fff4bf3 in semanage_direct_commit () from /lib64/libsemanage.so.1
#11 0x00007f608fff9fae in semanage_commit () from /lib64/libsemanage.so.1
#12 0x0000000000403e2b in main (argc=7, argv=0x7ffce2655058) at semodule.c:753
(gdb) f 3
#3 0x00007f6090096f59 in __avrule_xperm_setrangebits (low=30, high=30, xperms=0x8b9eea0)
at ../cil/src/cil_binary.c:1551
1551 xperms->perms[i] |= XPERM_SETBITS(h) - XPERM_SETBITS(low);
A signed integer overflow therefore occurs in XPERM_SETBITS(h):
#define XPERM_SETBITS(x) ((1 << (x & 0x1f)) - 1)
This macro is expanded with h=31, so "(1 << 31) - 1" is computed:
* (1 << 31) = -0x80000000 is the lowest signed 32-bit integer value
* (1 << 31) - 1 overflows the capacity of a signed 32-bit integer and
results in 0x7fffffff (which is unsigned)
Using unsigned integers (with "1U") fixes the crash, as
(1U << 31) = 0x80000000U has no overflowing issues.
Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
Acked-by: Petr Lautrbach <plautrba@redhat.com>
When classmaps used in a neverallow were being expanded during CIL
neverallow checking, an empty classmapping in the list of
classmappings for a classmap would cause the classmap expansion to
stop and the rest of the classmapping of the classmap to be ignored.
This would mean that not all of the classes and permissions associated
with the classmap would be used to check for a neverallow violation.
Do not end the expansion of a classmap when one classmapping is empty.
Reported-by: Jonathan Hettwer <j2468h@gmail.com>
Signed-off-by: James Carter <jwcart2@gmail.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
CIL was not correctly determining the depth of conditional expressions
which prevented it from giving an error when the max depth was exceeded.
This allowed invalid policy binaries to be created.
Validate the conditional expression using the same logic that is used
when evaluating a conditional expression. This includes checking the
depth of the expression.
Signed-off-by: James Carter <jwcart2@gmail.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
CIL was not correctly determining the depth of constraint expressions
which prevented it from giving an error when the max depth was exceeded.
This allowed invalid policy binaries with constraint expressions exceeding
the max depth to be created.
Validate the constraint expression using the same logic that is used
when reading the binary policy. This includes checking the depth of the
the expression.
Reported-by: Jonathan Hettwer <j2468h@gmail.com>
Signed-off-by: James Carter <jwcart2@gmail.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Implement a new, more space-efficient form of storing filename
transitions in the binary policy. The internal structures have already
been converted to this new representation; this patch just implements
reading/writing an equivalent representation from/to the binary policy.
This new format reduces the size of Fedora policy from 7.6 MB to only
3.3 MB (with policy optimization enabled in both cases). With the
unconfined module disabled, the size is reduced from 3.3 MB to 2.4 MB.
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
In preparation to support a new policy format with a more optimal
representation of filename transition rules, this patch applies an
equivalent change from kernel commit c3a276111ea2 ("selinux: optimize
storage of filename transitions").
See the kernel commit's description [1] for the rationale behind this
representation. This change doesn't bring any measurable difference of
policy build performance (semodule -B) on Fedora.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux.git/commit/?id=c3a276111ea2572399281988b3129683e2a6b60b
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
The comparison function, portcon_data_cmp(), only made use of the
protocol to put tcp before udp, dccp, and sctp. Rules that have
the same port range, but with different protocols would be considered
equal unless one of the protocols was tcp. When generating a CIL or
conf source policy from a binary or using the "-S" option in
checkpolicy the non-tcp portcon rules with the same port range would
not be consistently sorted.
Changed portcon_data_cmp() to sort portcon rules like the CIL function
cil_post_portcon_compare().
Reported-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: James Carter <jwcart2@gmail.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Improves writing of CIL category rules when converting MLS kernel
policy to CIL. No changes to functionality, but eliminate useless
checks for category aliases when using the p_cat_val_to_name array,
find the actual number of aliases before allocating memory, and
skip the category alias rules if there are no aliases.
Signed-off-by: James Carter <jwcart2@gmail.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Improves writing of CIL sensitivity rules when converting MLS kernel
policy to CIL. No changes to functionality, but eliminate useless
checks for sensitivity aliases when using the p_sens_val_to_name
array, find the actual number of aliases before allocating memory,
and skip the sensitivity alias rules if there are no aliases.
Signed-off-by: James Carter <jwcart2@gmail.com>
When converting a non-MLS kernel binary policy to CIL, write the CIL
default MLS rules (since CIL requires at least one sensitivity,
and sensitivityorder statements) on separate lines.
This improves the readability of the resulting CIL policy.
Signed-off-by: James Carter <jwcart2@gmail.com>
Type alias rules are not written out when converting a binary kernel
policy to a policy.conf. The problem is that type aliases are not in
the type_val_to_struct array and that is what is being used to find
the aliases.
Since type aliases are only in the types hashtable, walk that to
find the type aliases.
Fixed the syntax of the typalias rule which requires "alias" to come
between the type and the aliases (ex/ typealias TYPE alias ALIAS;).
Fixes: 0a08fd1e69 ("libsepol: Add ability to convert binary
policy to policy.conf file")
Signed-off-by: James Carter <jwcart2@gmail.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Type alias rules are not written out when converting a binary kernel
policy to CIL. The problem is that type aliases are not in the
type_val_to_struct array and that is what is being used to find the
aliases.
Since type aliases are only in the types hashtable, walk that to
find the type aliases.
Fixes: 70a480bfcd ("libsepol: Add ability to convert binary
policy to CIL")
Signed-off-by: James Carter <jwcart2@gmail.com>
CIL allows a type to be redeclared when using the multiple declarations
option ("-m" or "--muliple-decls"), but make it an error for an identifier
to be declared as both a type and an attribute.
Change the error message so that it always gives the location and flavor
of both declarations. The flavors will be the same in all other cases,
but in this case they explain why there is an error even if multiple
declartions are allowed.
Fixes: Commit fafe4c212b ("libsepol: cil: Add ability to redeclare types[attributes]")
Reported-by: Topi Miettinen <toiwoton@gmail.com>
Signed-off-by: James Carter <jwcart2@gmail.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Initialize the multiple_decls field when intializing the structure
cil_db.
Fixes: fafe4c212b ("libsepol: cil: Add ability to redeclare types[attributes]")
Reported-by: Topi Miettinen <toiwoton@gmail.com
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: James Carter <jwcart2@gmail.com>
As per the issue below, libsepol segfaults on loading old kernel policies
that contain duplicate filename transition rules. The segfault is due to
the fact that the val_to_name arrays have not yet been populated at this
point in the policydb_read() processing. Since this warning apparently
never worked since it was first introduced, drop it and just silently
discard the duplicate like the kernel does. I was not able to produce a
policy with such duplicates using the current policy toolchain, either
via CIL or via binary modules with manual semodule_link/expand.
Fixes: https://github.com/SELinuxProject/selinux/issues/239
Fixes: 8fdb225521 ("libsepol,checkpolicy: convert rangetrans and filenametrans to hashtabs")
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Acked-by: Ondrej Mosnacek <omosnace@redhat.com>
This reverts commit 692716fc5f.
Other parts of the SELinux userspace depend on certain attributes,
such as node_type, exisiting and this change breaks those parts.
Before this patch can be reapplied, we need to identify the attributes
that must never be expanded and create a CIL module with the needed
expandtypeattribute statements (or something similar).
Signed-off-by: James Carter <jwcarter@gmail.com>
Fix issues like:
<inline asm>:1:1: error: unknown directive
.symver cil_build_policydb_pdb, cil_build_policydb@LIBSEPOL_1.0
Which was caused by the DISABLE_SYMVER define not being defined
for static, Mac or Android builds.
Acked-by: Joshua Brindle <joshua.brindle@crunchydata.com>
Signed-off-by: William Roberts <william.c.roberts@intel.com>
James Carter
Nicolas Iooss
Petr Lautrbach
Evgeny Vereshchagin
Ondrej Mosnacek
Stephen Smalley
James Carter
William Roberts