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author | Linus Torvalds <torvalds@linux-foundation.org> | 2021-06-15 09:26:19 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-06-15 10:47:51 -0700 |
commit | 94f0b2d4a1d0c52035aef425da5e022bd2cb1c71 (patch) | |
tree | a646956edefb55000e34cf429e75add7b32f0367 /mm/hugetlb.c | |
parent | a33d62662d275cee22888fa7760fe09d5b9cd1f9 (diff) |
proc: only require mm_struct for writing
Commit 591a22c14d3f ("proc: Track /proc/$pid/attr/ opener mm_struct") we
started using __mem_open() to track the mm_struct at open-time, so that
we could then check it for writes.
But that also ended up making the permission checks at open time much
stricter - and not just for writes, but for reads too. And that in turn
caused a regression for at least Fedora 29, where NIC interfaces fail to
start when using NetworkManager.
Since only the write side wanted the mm_struct test, ignore any failures
by __mem_open() at open time, leaving reads unaffected. The write()
time verification of the mm_struct pointer will then catch the failure
case because a NULL pointer will not match a valid 'current->mm'.
Link: https://lore.kernel.org/netdev/YMjTlp2FSJYvoyFa@unreal/
Fixes: 591a22c14d3f ("proc: Track /proc/$pid/attr/ opener mm_struct")
Reported-and-tested-by: Leon Romanovsky <leon@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb.c')
0 files changed, 0 insertions, 0 deletions