| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.1 223/267] __bitmap_parselist: fix bug in empty string handling | Date | Fri, 31 Jul 2015 12:41:14 -0700 |
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4.1-stable review patch. If anyone has any objections, please let me know.
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From: Chris Metcalf <cmetcalf@ezchip.com>
commit 2528a8b8f457d7432552d0e2b6f0f4046bb702f4 upstream.
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 <cmetcalf@ezchip.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- lib/bitmap.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-)
--- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -506,12 +506,12 @@ static int __bitmap_parselist(const char 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 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 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;
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