proc: protect ptrace_may_access() with exec_update_lock (part 1)

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Fix the easy cases where procfs currently calls ptrace_may_access() without
exec_update_lock protection, where the fix is to simply add the extra lock
or use mm_access():

 - do_task_stat(): grab exec_update_lock
 - proc_pid_wchan(): grab exec_update_lock
 - proc_map_files_lookup(): use mm_access() instead of get_task_mm()
 - proc_map_files_readdir(): use mm_access() instead of get_task_mm()
 - proc_ns_get_link(): grab exec_update_lock
 - proc_ns_readlink(): grab exec_update_lock

Fixes: f83ce3e6b0 ("proc: avoid information leaks to non-privileged processes")
Cc: stable@vger.kernel.org
Signed-off-by: Jann Horn <jannh@google.com>
Link: https://patch.msgid.link/20260518-procfs-lockfix-part1-v1-1-5c3d20e0ac33@google.com
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>

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Jann Horn 2026-05-18 18:35:15 +02:00 • committed by Christian Brauner

parent a76640171b

commit 6650527444

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3 changed files with 40 additions and 19 deletions

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6

fs/proc/array.c

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43

fs/proc/base.c

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12

fs/proc/namespaces.c

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