mirror of
https://github.com/SELinuxProject/selinux
synced 2025-05-02 23:58:03 +00:00
ba9820a002
When the O_PATH emulation fails due to getxattr(2)/setxattr(2) failing
with ENOENT, e.g. because no procfs being available, override the errno
value to EBADF. This avoids confusion to the caller as it would suggest
the target of the operation does not exist, which is not the case:
setfiles: Could not set context for /: No such file or directory
Fixes: a782abf2 ("libselinux: emulate O_PATH support in fgetfilecon/fsetfilecon")
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: James Carter <jwcart2@gmail.com>
97 lines
1.8 KiB
C
97 lines
1.8 KiB
C
#include <unistd.h>
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#include <fcntl.h>
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#include <string.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <stdio.h>
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#include <sys/xattr.h>
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#include "selinux_internal.h"
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#include "policy.h"
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static ssize_t fgetxattr_wrapper(int fd, const char *name, void *value, size_t size) {
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char buf[40];
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int fd_flag, saved_errno = errno;
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ssize_t ret;
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ret = fgetxattr(fd, name, value, size);
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if (ret != -1 || errno != EBADF)
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return ret;
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/* Emulate O_PATH support */
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fd_flag = fcntl(fd, F_GETFL);
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if (fd_flag == -1 || (fd_flag & O_PATH) == 0) {
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errno = EBADF;
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return -1;
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}
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snprintf(buf, sizeof(buf), "/proc/self/fd/%d", fd);
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errno = saved_errno;
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ret = getxattr(buf, name, value, size);
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if (ret < 0 && errno == ENOENT)
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errno = EBADF;
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return ret;
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}
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int fgetfilecon_raw(int fd, char ** context)
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{
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char *buf;
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ssize_t size;
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ssize_t ret;
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size = INITCONTEXTLEN + 1;
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buf = malloc(size);
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if (!buf)
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return -1;
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memset(buf, 0, size);
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ret = fgetxattr_wrapper(fd, XATTR_NAME_SELINUX, buf, size - 1);
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if (ret < 0 && errno == ERANGE) {
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char *newbuf;
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size = fgetxattr_wrapper(fd, XATTR_NAME_SELINUX, NULL, 0);
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if (size < 0)
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goto out;
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size++;
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newbuf = realloc(buf, size);
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if (!newbuf)
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goto out;
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buf = newbuf;
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memset(buf, 0, size);
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ret = fgetxattr_wrapper(fd, XATTR_NAME_SELINUX, buf, size - 1);
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}
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out:
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if (ret == 0) {
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/* Re-map empty attribute values to errors. */
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errno = ENOTSUP;
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ret = -1;
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}
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if (ret < 0)
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free(buf);
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else
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*context = buf;
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return ret;
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}
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int fgetfilecon(int fd, char ** context)
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{
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char * rcontext = NULL;
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int ret;
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*context = NULL;
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ret = fgetfilecon_raw(fd, &rcontext);
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if (ret > 0) {
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ret = selinux_raw_to_trans_context(rcontext, context);
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freecon(rcontext);
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}
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if (ret >= 0 && *context)
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return strlen(*context) + 1;
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return ret;
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}
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