USB: gadget: u_f: add overflow checks to VLA macros
commit b1cd1b65af
upstream.
size can potentially hold an overflowed value if its assigned expression
is left unchecked, leading to a smaller than needed allocation when
vla_group_size() is used by callers to allocate memory.
To fix this, add a test for saturation before declaring variables and an
overflow check to (n) * sizeof(type).
If the expression results in overflow, vla_group_size() will return SIZE_MAX.
Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Brooke Basile <brookebasile@gmail.com>
Acked-by: Felipe Balbi <balbi@kernel.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
5.4-rM2-2.2.x-imx-squashed
parent
2534d3dec3
commit
f47ab852be
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@ -14,6 +14,7 @@
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#define __U_F_H__
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#include <linux/usb/gadget.h>
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#include <linux/overflow.h>
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/* Variable Length Array Macros **********************************************/
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#define vla_group(groupname) size_t groupname##__next = 0
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@ -21,21 +22,36 @@
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#define vla_item(groupname, type, name, n) \
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size_t groupname##_##name##__offset = ({ \
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size_t align_mask = __alignof__(type) - 1; \
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size_t offset = (groupname##__next + align_mask) & ~align_mask;\
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size_t size = (n) * sizeof(type); \
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groupname##__next = offset + size; \
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size_t offset = 0; \
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if (groupname##__next != SIZE_MAX) { \
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size_t align_mask = __alignof__(type) - 1; \
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size_t offset = (groupname##__next + align_mask) \
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& ~align_mask; \
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size_t size = array_size(n, sizeof(type)); \
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if (check_add_overflow(offset, size, \
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&groupname##__next)) { \
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groupname##__next = SIZE_MAX; \
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offset = 0; \
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} \
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} \
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offset; \
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})
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#define vla_item_with_sz(groupname, type, name, n) \
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size_t groupname##_##name##__sz = (n) * sizeof(type); \
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size_t groupname##_##name##__offset = ({ \
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size_t align_mask = __alignof__(type) - 1; \
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size_t offset = (groupname##__next + align_mask) & ~align_mask;\
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size_t size = groupname##_##name##__sz; \
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groupname##__next = offset + size; \
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offset; \
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size_t groupname##_##name##__sz = array_size(n, sizeof(type)); \
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size_t groupname##_##name##__offset = ({ \
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size_t offset = 0; \
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if (groupname##__next != SIZE_MAX) { \
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size_t align_mask = __alignof__(type) - 1; \
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size_t offset = (groupname##__next + align_mask) \
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& ~align_mask; \
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if (check_add_overflow(offset, groupname##_##name##__sz,\
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&groupname##__next)) { \
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groupname##__next = SIZE_MAX; \
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offset = 0; \
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} \
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} \
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offset; \
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})
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#define vla_ptr(ptr, groupname, name) \
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