4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Yury Norov <[email protected]> commit 8351760ff5b2042039554b4948ddabaac644a976 upstream. syzbot is catching stalls at __bitmap_parselist() (https://syzkaller.appspot.com/bug?id=ad7e0351fbc90535558514a71cd3edc11681997a). The trigger is unsigned long v = 0; bitmap_parselist("7:,", &v, BITS_PER_LONG); which results in hitting infinite loop at while (a <= b) { off = min(b - a + 1, used_size); bitmap_set(maskp, a, off); a += group_size; } due to used_size == group_size == 0. Link: http://lkml.kernel.org/r/[email protected] Fixes: 0a5ce0831d04382a ("lib/bitmap.c: make bitmap_parselist() thread-safe and much faster") Signed-off-by: Yury Norov <[email protected]> Reported-by: Tetsuo Handa <[email protected]> Reported-by: syzbot <[email protected]> Cc: Noam Camus <[email protected]> Cc: Rasmus Villemoes <[email protected]> Cc: Matthew Wilcox <[email protected]> Cc: Mauro Carvalho Chehab <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- lib/bitmap.c | 2 +- lib/test_bitmap.c | 4 ++++ 2 files changed, 5 insertions(+), 1 deletion(-) --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -605,7 +605,7 @@ static int __bitmap_parselist(const char /* if no digit is after '-', it's wrong*/ if (at_start && in_range) return -EINVAL; - if (!(a <= b) || !(used_size <= group_size)) + if (!(a <= b) || group_size == 0 || !(used_size <= group_size)) return -EINVAL; if (b >= nmaskbits) return -ERANGE; --- a/lib/test_bitmap.c +++ b/lib/test_bitmap.c @@ -218,6 +218,10 @@ static const struct test_bitmap_parselis {-EINVAL, "-1", NULL, 8, 0}, {-EINVAL, "-0", NULL, 8, 0}, {-EINVAL, "10-1", NULL, 8, 0}, + {-EINVAL, "0-31:", NULL, 8, 0}, + {-EINVAL, "0-31:0", NULL, 8, 0}, + {-EINVAL, "0-31:0/0", NULL, 8, 0}, + {-EINVAL, "0-31:1/0", NULL, 8, 0}, {-EINVAL, "0-31:10/1", NULL, 8, 0}, };
