Author: andrew Date: Fri Oct 4 14:10:56 2019 New Revision: 353104 URL: https://svnweb.freebsd.org/changeset/base/353104
Log: MFS r353032: Check the vfs option length is valid before accessing through When a VFS option passed to nmount is present but NULL the kernel will place an empty option in its internal list. This will have a NULL pointer and a length of 0. When we come to read one of these the kernel will try to load from the last address of virtual memory. This is normally invalid so will fault resulting in a kernel panic. Fix this by checking if the length is valid before dereferencing. Approved by: re (kib) Sponsored by: DARPA, AFRL Modified: releng/12.1/sys/kern/vfs_mount.c Directory Properties: releng/12.1/ (props changed) Modified: releng/12.1/sys/kern/vfs_mount.c ============================================================================== --- releng/12.1/sys/kern/vfs_mount.c Fri Oct 4 13:43:07 2019 (r353103) +++ releng/12.1/sys/kern/vfs_mount.c Fri Oct 4 14:10:56 2019 (r353104) @@ -603,7 +603,7 @@ vfs_donmount(struct thread *td, uint64_t fsflags, stru */ fstypelen = 0; error = vfs_getopt(optlist, "fstype", (void **)&fstype, &fstypelen); - if (error || fstype[fstypelen - 1] != '\0') { + if (error || fstypelen <= 0 || fstype[fstypelen - 1] != '\0') { error = EINVAL; if (errmsg != NULL) strncpy(errmsg, "Invalid fstype", errmsg_len); @@ -611,7 +611,7 @@ vfs_donmount(struct thread *td, uint64_t fsflags, stru } fspathlen = 0; error = vfs_getopt(optlist, "fspath", (void **)&fspath, &fspathlen); - if (error || fspath[fspathlen - 1] != '\0') { + if (error || fspathlen <= 0 || fspath[fspathlen - 1] != '\0') { error = EINVAL; if (errmsg != NULL) strncpy(errmsg, "Invalid fspath", errmsg_len); _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"