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https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-09-17 01:39:30 -05:00
Benjamin Marzinski
1c61b0a6e5
The *_bit_le functions use a signed integer for the bit number. However, the *_bit functions can use an unsigned long. This causes problems if there is a large bitmap and a bit number > 0x80000000 is passed in. Since that is a negative int, it will get sign extended to a long when getting passed to the *_bit function, turning it into a huge bit number. This usually ends up with the memory address wrapping around and the function accessing memory before the start of the bitmap. Avoid this by making the *_bit_le functions take an unsigned long. This can be triggered by faking an almost 4TB dm-mirror device, which uses bitmaps to track the mirror regions: $ dmsetup create bigzero --table '0 8589934590 zero' $ dmsetup create mymirror --table '0 8589934590 mirror core 2 2 nosync 2 /dev/mapper/bigzero 0 /dev/mapper/bigzero 0' This will access memory before the start of the sync_bits bitmap, and likely hit the guard page of the previously allocated clean_bits bitmap, causing a kernel panic with the old code. I looked and didn't see any crazy code using the signed int to intentionally try and access bits before some address within the bitmap. Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com> Signed-off-by: Yury Norov <ynorov@nvidia.com>
65 lines
1.4 KiB
C
65 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_GENERIC_BITOPS_LE_H_
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#define _ASM_GENERIC_BITOPS_LE_H_
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#include <asm/types.h>
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#include <asm/byteorder.h>
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#if defined(__LITTLE_ENDIAN)
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#define BITOP_LE_SWIZZLE 0
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#elif defined(__BIG_ENDIAN)
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#define BITOP_LE_SWIZZLE ((BITS_PER_LONG-1) & ~0x7)
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#endif
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static inline int test_bit_le(unsigned long nr, const void *addr)
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{
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return test_bit(nr ^ BITOP_LE_SWIZZLE, addr);
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}
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static inline void set_bit_le(unsigned long nr, void *addr)
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{
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set_bit(nr ^ BITOP_LE_SWIZZLE, addr);
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}
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static inline void clear_bit_le(unsigned long nr, void *addr)
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{
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clear_bit(nr ^ BITOP_LE_SWIZZLE, addr);
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}
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static inline void __set_bit_le(unsigned long nr, void *addr)
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{
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__set_bit(nr ^ BITOP_LE_SWIZZLE, addr);
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}
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static inline void __clear_bit_le(unsigned long nr, void *addr)
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{
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__clear_bit(nr ^ BITOP_LE_SWIZZLE, addr);
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}
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static inline int test_and_set_bit_le(unsigned long nr, void *addr)
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{
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return test_and_set_bit(nr ^ BITOP_LE_SWIZZLE, addr);
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}
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static inline int test_and_clear_bit_le(unsigned long nr, void *addr)
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{
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return test_and_clear_bit(nr ^ BITOP_LE_SWIZZLE, addr);
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}
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static inline int __test_and_set_bit_le(unsigned long nr, void *addr)
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{
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return __test_and_set_bit(nr ^ BITOP_LE_SWIZZLE, addr);
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}
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static inline int __test_and_clear_bit_le(unsigned long nr, void *addr)
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{
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return __test_and_clear_bit(nr ^ BITOP_LE_SWIZZLE, addr);
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}
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#endif /* _ASM_GENERIC_BITOPS_LE_H_ */
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