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authorSimon Ser <contact@emersion.fr>2022-05-12 19:58:50 +0200
committerSimon Ser <contact@emersion.fr>2022-05-12 19:58:50 +0200
commit19896e7fb63db73c4a66b68a79d7cbd039198a1d (patch)
tree0c10ae22d04c1633cf700af5fa569c2f0f59a7e9 /util
parente646d882cf4949d290fff2ba3b7ae4c124f6f13d (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.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/util/shm.c b/util/shm.c
index e0d84e8e..6fddebbb 100644
--- a/util/shm.c
+++ b/util/shm.c
@@ -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);