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authorEric W. Biederman <ebiederm@xmission.com>2021-10-16 12:47:51 -0500
committerEric W. Biederman <ebiederm@xmission.com>2021-10-19 11:04:25 -0500
commit34dc2fd6e6908499b669c7b45320cddf38b332e1 (patch)
tree5674fdd26d21efd860afc4c571c250cfa511aed0 /kernel/cred.c
parent629715adc62b0ad27ab04d0aa73a71927f886910 (diff)
downloadlwn-34dc2fd6e6908499b669c7b45320cddf38b332e1.tar.gz
lwn-34dc2fd6e6908499b669c7b45320cddf38b332e1.zip
ucounts: Proper error handling in set_cred_ucounts
Instead of leaking the ucounts in new if alloc_ucounts fails, store the result of alloc_ucounts into a temporary variable, which is later assigned to new->ucounts. Cc: stable@vger.kernel.org Fixes: 905ae01c4ae2 ("Add a reference to ucounts for each cred") Link: https://lkml.kernel.org/r/87pms2s0v8.fsf_-_@disp2133 Tested-by: Yu Zhao <yuzhao@google.com> Reviewed-by: Alexey Gladkov <legion@kernel.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'kernel/cred.c')
-rw-r--r--kernel/cred.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/cred.c b/kernel/cred.c
index 3d163bfd64a9..16c05dfbec4d 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -669,7 +669,7 @@ int set_cred_ucounts(struct cred *new)
{
struct task_struct *task = current;
const struct cred *old = task->real_cred;
- struct ucounts *old_ucounts = new->ucounts;
+ struct ucounts *new_ucounts, *old_ucounts = new->ucounts;
if (new->user == old->user && new->user_ns == old->user_ns)
return 0;
@@ -681,9 +681,10 @@ int set_cred_ucounts(struct cred *new)
if (old_ucounts && old_ucounts->ns == new->user_ns && uid_eq(old_ucounts->uid, new->euid))
return 0;
- if (!(new->ucounts = alloc_ucounts(new->user_ns, new->euid)))
+ if (!(new_ucounts = alloc_ucounts(new->user_ns, new->euid)))
return -EAGAIN;
+ new->ucounts = new_ucounts;
if (old_ucounts)
put_ucounts(old_ucounts);