Author: kevans Date: Mon Aug 31 15:07:15 2020 New Revision: 364990 URL: https://svnweb.freebsd.org/changeset/base/364990
Log: posixshm: fix setting of shm_flags Noted in D24652, we currently set shmfd->shm_flags on every shm_open()/shm_open2(). This wasn't properly thought out; one shouldn't be able to specify incompatible flags on subsequent opens of non-anon shm. Move setting of shm_flags explicitly to the two places shmfd are created, as we do with seals, and validate when we're opening a pre-existing mapping that we've either passed no flags or we've passed the exact same flags as the first time. Reviewed by: kib, markj Differential Revision: https://reviews.freebsd.org/D26242 Modified: head/sys/kern/uipc_shm.c Modified: head/sys/kern/uipc_shm.c ============================================================================== --- head/sys/kern/uipc_shm.c Mon Aug 31 15:03:23 2020 (r364989) +++ head/sys/kern/uipc_shm.c Mon Aug 31 15:07:15 2020 (r364990) @@ -833,6 +833,7 @@ kern_shm_open2(struct thread *td, const char *userpath } shmfd = shm_alloc(td->td_ucred, cmode); shmfd->shm_seals = initial_seals; + shmfd->shm_flags = shmflags; } else { error = shm_copyin_path(td, userpath, &path); if (error != 0) { @@ -855,6 +856,7 @@ kern_shm_open2(struct thread *td, const char *userpath #endif shmfd = shm_alloc(td->td_ucred, cmode); shmfd->shm_seals = initial_seals; + shmfd->shm_flags = shmflags; shm_insert(path, fnv, shmfd); #ifdef MAC } @@ -898,6 +900,8 @@ kern_shm_open2(struct thread *td, const char *userpath else if ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL)) error = EEXIST; + else if (shmflags != 0 && shmflags != shmfd->shm_flags) + error = EINVAL; else { #ifdef MAC error = mac_posixshm_check_open(td->td_ucred, @@ -947,7 +951,6 @@ kern_shm_open2(struct thread *td, const char *userpath } } - shmfd->shm_flags = shmflags; finit(fp, FFLAGS(flags & O_ACCMODE), DTYPE_SHM, shmfd, &shm_ops); td->td_retval[0] = fd; _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "[email protected]"
