diff options
author | Simon Ser <contact@emersion.fr> | 2022-05-12 19:58:50 +0200 |
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committer | Simon Ser <contact@emersion.fr> | 2022-05-12 19:58:50 +0200 |
commit | 19896e7fb63db73c4a66b68a79d7cbd039198a1d (patch) | |
tree | 0c10ae22d04c1633cf700af5fa569c2f0f59a7e9 /util | |
parent | e646d882cf4949d290fff2ba3b7ae4c124f6f13d (diff) |
util/shm: clear mode permission bits in allocate_shm_file_pair
This ensures the file cannot be re-opened with write permissions.
Closes: https://gitlab.freedesktop.org/wlroots/wlroots/-/issues/3429
Diffstat (limited to 'util')
-rw-r--r-- | util/shm.c | 9 |
1 files changed, 9 insertions, 0 deletions
@@ -3,6 +3,7 @@ #include <fcntl.h> #include <string.h> #include <sys/mman.h> +#include <sys/stat.h> #include <time.h> #include <unistd.h> #include <wlr/config.h> @@ -73,6 +74,14 @@ bool allocate_shm_file_pair(size_t size, int *rw_fd_ptr, int *ro_fd_ptr) { shm_unlink(name); + // Make sure the file cannot be re-opened in read-write mode (e.g. via + // "/proc/self/fd/" on Linux) + if (fchmod(rw_fd, 0) != 0) { + close(rw_fd); + close(ro_fd); + return false; + } + int ret; do { ret = ftruncate(rw_fd, size); |