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authorAlexey Gladkov <legion@kernel.org>2021-04-22 14:27:09 +0200
committerEric W. Biederman <ebiederm@xmission.com>2021-04-30 14:14:00 -0500
commit905ae01c4ae2ae3df05bb141801b1db4b7d83c61 (patch)
treec4216c817bd6859c8028a25900bcfe4330c1e3c9 /kernel/sys.c
parentf9c82a4ea89c384d49ce03768ba88d049ed3f1f0 (diff)
Add a reference to ucounts for each cred
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>
Diffstat (limited to 'kernel/sys.c')
-rw-r--r--kernel/sys.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/kernel/sys.c b/kernel/sys.c
index 2e2e3f378d97..cabfc5b86175 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -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: