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libselinux: Fix mmap memory release for file labeling 

Ensure the mmap start address and length are not modified so the memory
used can be released when selabel_close(3) is called.

Signed-off-by: Richard Haines <richard_c_haines@btinternet.com>
This commit is contained in:
Richard Haines 2015-09-15 14:33:05 +01:00 committed by Stephen Smalley
parent 1e50aefea5
commit 5d19497b5c
2 changed files with 14 additions and 12 deletions
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12
libselinux/src/label_file.c
View File

@ -159,8 +159,8 @@ static int load_mmap(struct selabel_handle *rec, const char *path,
} }
/* save where we mmap'd the file to cleanup on close() */ /* save where we mmap'd the file to cleanup on close() */
mmap_area->addr = addr; mmap_area->addr = mmap_area->next_addr = addr;
mmap_area->len = len; mmap_area->len = mmap_area->next_len = len;
mmap_area->next = data->mmap_areas; mmap_area->next = data->mmap_areas;
data->mmap_areas = mmap_area; data->mmap_areas = mmap_area;
@ -231,7 +231,7 @@ static int load_mmap(struct selabel_handle *rec, const char *path,
/* Check for stem_len wrap around. */ /* Check for stem_len wrap around. */
if (stem_len < UINT32_MAX) { if (stem_len < UINT32_MAX) {
buf = (char *)mmap_area->addr; buf = (char *)mmap_area->next_addr;
/* Check if over-run before null check. */ /* Check if over-run before null check. */
rc = next_entry(NULL, mmap_area, (stem_len + 1)); rc = next_entry(NULL, mmap_area, (stem_len + 1));
if (rc < 0) if (rc < 0)
@ -317,7 +317,7 @@ static int load_mmap(struct selabel_handle *rec, const char *path,
goto err; goto err;
} }
spec->regex_str = (char *)mmap_area->addr; spec->regex_str = (char *)mmap_area->next_addr;
rc = next_entry(NULL, mmap_area, entry_len); rc = next_entry(NULL, mmap_area, entry_len);
if (rc < 0) if (rc < 0)
goto err; goto err;
@ -369,7 +369,7 @@ static int load_mmap(struct selabel_handle *rec, const char *path,
rc = -1; rc = -1;
goto err; goto err;
} }
spec->regex = (pcre *)mmap_area->addr; spec->regex = (pcre *)mmap_area->next_addr;
rc = next_entry(NULL, mmap_area, entry_len); rc = next_entry(NULL, mmap_area, entry_len);
if (rc < 0) if (rc < 0)
goto err; goto err;
@ -387,7 +387,7 @@ static int load_mmap(struct selabel_handle *rec, const char *path,
rc = -1; rc = -1;
goto err; goto err;
} }
spec->lsd.study_data = (void *)mmap_area->addr; spec->lsd.study_data = (void *)mmap_area->next_addr;
spec->lsd.flags |= PCRE_EXTRA_STUDY_DATA; spec->lsd.flags |= PCRE_EXTRA_STUDY_DATA;
rc = next_entry(NULL, mmap_area, entry_len); rc = next_entry(NULL, mmap_area, entry_len);
if (rc < 0) if (rc < 0)

14
libselinux/src/label_file.h
View File

@ -49,8 +49,10 @@ struct stem {
/* Where we map the file in during selabel_open() */ /* Where we map the file in during selabel_open() */
struct mmap_area { struct mmap_area {
void *addr; /* Start of area - gets incremented by next_entry() */ void *addr; /* Start addr + len used to release memory at close */
size_t len; /* Length - gets decremented by next_entry() */ size_t len;
void *next_addr; /* Incremented by next_entry() */
size_t next_len; /* Decremented by next_entry() */
struct mmap_area *next; struct mmap_area *next;
}; };
@ -310,14 +312,14 @@ static inline int find_stem_from_spec(struct saved_data *data, const char *buf)
* current buffer). */ * current buffer). */
static inline int next_entry(void *buf, struct mmap_area *fp, size_t bytes) static inline int next_entry(void *buf, struct mmap_area *fp, size_t bytes)
{ {
if (bytes > fp->len) if (bytes > fp->next_len)
return -1; return -1;
if (buf) if (buf)
memcpy(buf, fp->addr, bytes); memcpy(buf, fp->next_addr, bytes);
fp->addr = (char *)fp->addr + bytes; fp->next_addr = (char *)fp->next_addr + bytes;
fp->len -= bytes; fp->next_len -= bytes;
return 0; return 0;
} }