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| author |   Alexey Gladkov <legion@kernel.org> | 2021-04-22 14:27:09 +0200 |
|---|---|---|
| committer |   Eric W. Biederman <ebiederm@xmission.com> | 2021-04-30 14:14:00 -0500 |
| commit | 905ae01c4ae2ae3df05bb141801b1db4b7d83c61 (patch) | |
| tree | c4216c817bd6859c8028a25900bcfe4330c1e3c9 /kernel/sys.c | |
| parent | Increase size of ucounts to atomic_long_t (diff) | |
| download | linux-dev-905ae01c4ae2ae3df05bb141801b1db4b7d83c61.tar.xz linux-dev-905ae01c4ae2ae3df05bb141801b1db4b7d83c61.zip | |
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.c | 12 |
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: |