diff options
Diffstat (limited to 'util/fusermount.c')
| -rw-r--r-- | util/fusermount.c | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/util/fusermount.c b/util/fusermount.c index a3cf513..0e1d34d 100644 --- a/util/fusermount.c +++ b/util/fusermount.c @@ -711,6 +711,23 @@ static int get_string_opt(const char *s, unsigned len, const char *opt, return 1; } +/* The kernel silently truncates the "data" argument to PAGE_SIZE-1 characters. + * This can be dangerous if it e.g. truncates the option "group_id=1000" to + * "group_id=1". + * This wrapper detects this case and bails out with an error. + */ +static int mount_notrunc(const char *source, const char *target, + const char *filesystemtype, unsigned long mountflags, + const char *data) { + if (strlen(data) > sysconf(_SC_PAGESIZE) - 1) { + fprintf(stderr, "%s: mount options too long\n", progname); + errno = EINVAL; + return -1; + } + return mount(source, target, filesystemtype, mountflags, data); +} + + static int do_mount(const char *mnt, char **typep, mode_t rootmode, int fd, const char *opts, const char *dev, char **sourcep, char **mnt_optsp) @@ -828,7 +845,7 @@ static int do_mount(const char *mnt, char **typep, mode_t rootmode, else strcpy(source, subtype ? subtype : dev); - res = mount(source, mnt, type, flags, optbuf); + res = mount_notrunc(source, mnt, type, flags, optbuf); if (res == -1 && errno == ENODEV && subtype) { /* Probably missing subtype support */ strcpy(type, blkdev ? "fuseblk" : "fuse"); @@ -839,13 +856,13 @@ static int do_mount(const char *mnt, char **typep, mode_t rootmode, strcpy(source, type); } - res = mount(source, mnt, type, flags, optbuf); + res = mount_notrunc(source, mnt, type, flags, optbuf); } if (res == -1 && errno == EINVAL) { /* It could be an old version not supporting group_id */ sprintf(d, "fd=%i,rootmode=%o,user_id=%u", fd, rootmode, getuid()); - res = mount(source, mnt, type, flags, optbuf); + res = mount_notrunc(source, mnt, type, flags, optbuf); } if (res == -1) { int errno_save = errno; |