diff options
Diffstat (limited to 'ipc')
| -rw-r--r-- | ipc/shm.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/ipc/shm.c b/ipc/shm.c index 32b65f7a2dba..9c687cda9b0a 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -1127,9 +1127,17 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, goto out; else if ((addr = (ulong)shmaddr)) { if (addr & (shmlba - 1)) { - if (shmflg & SHM_RND) + if (shmflg & SHM_RND) { addr &= ~(shmlba - 1); /* round down */ - else + + /* + * Ensure that the round-down is non-nil + * when remapping. This can happen for + * cases when addr < shmlba. + */ + if (!addr && (shmflg & SHM_REMAP)) + goto out; + } else #ifndef __ARCH_FORCE_SHMLBA if (addr & ~PAGE_MASK) #endif |