4.14-stable review patch. If anyone has any objections, please let me know.
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From: Aleksa Sarai cyphar@cyphar.com
commit ccf61486fe1e1a48e18c638d1813cda77b3c0737 upstream.
Due to an oversight in commit 1b3044e39a89 ("procfs: fix pthread cross-thread naming if !PR_DUMPABLE") in switching from REG to NOD, chmod operations on /proc/thread-self/comm were no longer blocked as they are on almost all other procfs files.
A very similar situation with /proc/self/environ was used to as a root exploit a long time ago, but procfs has SB_I_NOEXEC so this is simply a correctness issue.
Ref: https://lwn.net/Articles/191954/ Ref: 6d76fa58b050 ("Don't allow chmod() on the /proc/<pid>/ files") Fixes: 1b3044e39a89 ("procfs: fix pthread cross-thread naming if !PR_DUMPABLE") Cc: stable@vger.kernel.org # v4.7+ Signed-off-by: Aleksa Sarai cyphar@cyphar.com Message-Id: 20230713141001.27046-1-cyphar@cyphar.com Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/proc/base.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -3335,7 +3335,8 @@ static int proc_tid_comm_permission(stru }
static const struct inode_operations proc_tid_comm_inode_operations = { - .permission = proc_tid_comm_permission, + .setattr = proc_setattr, + .permission = proc_tid_comm_permission, };
/*