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ext4: fix undefined behavior in bit shift for ext4_check_flag_values
jira VULN-155618 cve CVE-2022-50403 commit-author Gaosheng Cui <cuigaosheng1@huawei.com> commit 3bf678a Shifting signed 32-bit value by 31 bits is undefined, so changing significant bit to unsigned. The UBSAN warning calltrace like below: UBSAN: shift-out-of-bounds in fs/ext4/ext4.h:591:2 left shift of 1 by 31 places cannot be represented in type 'int' Call Trace: <TASK> dump_stack_lvl+0x7d/0xa5 dump_stack+0x15/0x1b ubsan_epilogue+0xe/0x4e __ubsan_handle_shift_out_of_bounds+0x1e7/0x20c ext4_init_fs+0x5a/0x277 do_one_initcall+0x76/0x430 kernel_init_freeable+0x3b3/0x422 kernel_init+0x24/0x1e0 ret_from_fork+0x1f/0x30 </TASK> Fixes: 9a4c801 ("ext4: ensure Inode flags consistency are checked at build time") Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com> Link: https://lore.kernel.org/r/20221031055833.3966222-1-cuigaosheng1@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org (cherry picked from commit 3bf678a) Signed-off-by: Jonathan Maple <jmaple@ciq.com>
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fs/ext4/ext4.h

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@@ -512,7 +512,7 @@ enum {
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*
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* It's not paranoia if the Murphy's Law really *is* out to get you. :-)
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*/
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#define TEST_FLAG_VALUE(FLAG) (EXT4_##FLAG##_FL == (1 << EXT4_INODE_##FLAG))
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#define TEST_FLAG_VALUE(FLAG) (EXT4_##FLAG##_FL == (1U << EXT4_INODE_##FLAG))
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#define CHECK_FLAG_VALUE(FLAG) BUILD_BUG_ON(!TEST_FLAG_VALUE(FLAG))
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static inline void ext4_check_flag_values(void)

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