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982f7c2b2e
The semctl syscall has several code paths that lead to the leakage of uninitialized kernel stack memory (namely the IPC_INFO, SEM_INFO, IPC_STAT, and SEM_STAT commands) during the use of the older, obsolete version of the semid_ds struct. The copy_semid_to_user() function declares a semid_ds struct on the stack and copies it back to the user without initializing or zeroing the "sem_base", "sem_pending", "sem_pending_last", and "undo" pointers, allowing the leakage of 16 bytes of kernel stack memory. The code is still reachable on 32-bit systems - when calling semctl() newer glibc's automatically OR the IPC command with the IPC_64 flag, but invoking the syscall directly allows users to use the older versions of the struct. Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>