ich777/linux_media
1
0
Fork 0
mirror of https://github.com/tbsdtv/linux_media.git synced 2025-07-23 04:33:26 +02:00
Code Issues Packages Projects Releases Wiki Activity

Add a reference to ucounts for each cred

Browse Source 
For RLIMIT_NPROC and some other rlimits the user_struct that holds the
global limit is kept alive for the lifetime of a process by keeping it
in struct cred. Adding a pointer to ucounts in the struct cred will
allow to track RLIMIT_NPROC not only for user in the system, but for
user in the user_namespace.

Updating ucounts may require memory allocation which may fail. So, we
cannot change cred.ucounts in the commit_creds() because this function
cannot fail and it should always return 0. For this reason, we modify
cred.ucounts before calling the commit_creds().

Changelog

v6:
* Fix null-ptr-deref in is_ucounts_overlimit() detected by trinity. This
  error was caused by the fact that cred_alloc_blank() left the ucounts
  pointer empty.

Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Alexey Gladkov <legion@kernel.org>
Link: https://lkml.kernel.org/r/b37aaef28d8b9b0d757e07ba6dd27281bbe39259.1619094428.git.legion@kernel.org
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
This commit is contained in:
Alexey Gladkov
2021-04-22 14:27:09 +02:00
committed by Eric W. Biederman
parent f9c82a4ea8
commit 905ae01c4a
8 changed files with 108 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
kernel/sys.c
View File

@@ -552,6 +552,10 @@ long __sys_setreuid(uid_t ruid, uid_t euid)
if (retval < 0)
goto error;
retval = set_cred_ucounts(new);
if (retval < 0)
goto error;
return commit_creds(new);
error:
@@ -610,6 +614,10 @@ long __sys_setuid(uid_t uid)
if (retval < 0)
goto error;
retval = set_cred_ucounts(new);
if (retval < 0)
goto error;
return commit_creds(new);
error:
@@ -685,6 +693,10 @@ long __sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
if (retval < 0)
goto error;
retval = set_cred_ucounts(new);
if (retval < 0)
goto error;
return commit_creds(new);
error: