From 2528a8b8f457d7432552d0e2b6f0f4046bb702f4 Mon Sep 17 00:00:00 2001 From: Chris Metcalf Date: Thu, 25 Jun 2015 15:02:08 -0700 Subject: [PATCH] __bitmap_parselist: fix bug in empty string handling bitmap_parselist("", &mask, nmaskbits) will erroneously set bit zero in the mask. The same bug is visible in cpumask_parselist() since it is layered on top of the bitmask code, e.g. if you boot with "isolcpus=", you will actually end up with cpu zero isolated. The bug was introduced in commit 4b060420a596 ("bitmap, irq: add smp_affinity_list interface to /proc/irq") when bitmap_parselist() was generalized to support userspace as well as kernelspace. Fixes: 4b060420a596 ("bitmap, irq: add smp_affinity_list interface to /proc/irq") Signed-off-by: Chris Metcalf Cc: Rasmus Villemoes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/bitmap.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/lib/bitmap.c b/lib/bitmap.c index 64c0926f5dd8..40162f87ea2d 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -506,12 +506,12 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen, unsigned a, b; int c, old_c, totaldigits; const char __user __force *ubuf = (const char __user __force *)buf; - int exp_digit, in_range; + int at_start, in_range; totaldigits = c = 0; bitmap_zero(maskp, nmaskbits); do { - exp_digit = 1; + at_start = 1; in_range = 0; a = b = 0; @@ -540,11 +540,10 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen, break; if (c == '-') { - if (exp_digit || in_range) + if (at_start || in_range) return -EINVAL; b = 0; in_range = 1; - exp_digit = 1; continue; } @@ -554,16 +553,18 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen, b = b * 10 + (c - '0'); if (!in_range) a = b; - exp_digit = 0; + at_start = 0; totaldigits++; } if (!(a <= b)) return -EINVAL; if (b >= nmaskbits) return -ERANGE; - while (a <= b) { - set_bit(a, maskp); - a++; + if (!at_start) { + while (a <= b) { + set_bit(a, maskp); + a++; + } } } while (buflen && c == ','); return 0; -- 2.34.1