exec: Make sure task->comm is always NUL-terminated

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Using strscpy() meant that the final character in task->comm may be
non-NUL for a moment before the "string too long" truncation happens.

Instead of adding a new use of the ambiguous strncpy(), we'd want to
use memtostr_pad() which enforces being able to check at compile time
that sizes are sensible, but this requires being able to see string
buffer lengths. Instead of trying to inline __set_task_comm() (which
needs to call trace and perf functions), just open-code it. But to
make sure we're always safe, add compile-time checking like we already
do for get_task_comm().

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Kees Cook <kees@kernel.org>

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This commit is contained in:

Kees Cook 2024-11-29 20:06:55 -08:00

parent fa1bdca98d

commit 3a3f61ce5e

5 changed files with 14 additions and 14 deletions

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12

fs/exec.c

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9

include/linux/sched.h

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2

io_uring/io-wq.c

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2

io_uring/sqpoll.c

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3

kernel/kthread.c

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