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| author | Brooke Basile <brookebasile@gmail.com> | 2020-08-25 09:05:08 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-08-25 16:02:29 +0200 |
| commit | b1cd1b65afba95971fa457dfdb2c941c60d38c5b (patch) | |
| tree | efcb72facdda141d12b4f43b1cf6279d5cfa49c1 | |
| parent | f1ec7ae6c9f8c016db320e204cb519a1da1581b8 (diff) | |
| download | linux-visconti-b1cd1b65afba95971fa457dfdb2c941c60d38c5b.tar.gz | |
USB: gadget: u_f: add overflow checks to VLA macros
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>
| -rw-r--r-- | drivers/usb/gadget/u_f.h | 38 |
1 files changed, 27 insertions, 11 deletions
diff --git a/drivers/usb/gadget/u_f.h b/drivers/usb/gadget/u_f.h index eaa13fd3dc7f36..df4e1dcb357dff 100644 --- a/drivers/usb/gadget/u_f.h +++ b/drivers/usb/gadget/u_f.h @@ -14,6 +14,7 @@ #define __U_F_H__ #include <linux/usb/gadget.h> +#include <linux/overflow.h> /* Variable Length Array Macros **********************************************/ #define vla_group(groupname) size_t groupname##__next = 0 @@ -21,21 +22,36 @@ #define vla_item(groupname, type, name, n) \ size_t groupname##_##name##__offset = ({ \ - size_t align_mask = __alignof__(type) - 1; \ - size_t offset = (groupname##__next + align_mask) & ~align_mask;\ - size_t size = (n) * sizeof(type); \ - groupname##__next = offset + size; \ + size_t offset = 0; \ + if (groupname##__next != SIZE_MAX) { \ + size_t align_mask = __alignof__(type) - 1; \ + size_t offset = (groupname##__next + align_mask) \ + & ~align_mask; \ + size_t size = array_size(n, sizeof(type)); \ + if (check_add_overflow(offset, size, \ + &groupname##__next)) { \ + groupname##__next = SIZE_MAX; \ + offset = 0; \ + } \ + } \ offset; \ }) #define vla_item_with_sz(groupname, type, name, n) \ - size_t groupname##_##name##__sz = (n) * sizeof(type); \ - size_t groupname##_##name##__offset = ({ \ - size_t align_mask = __alignof__(type) - 1; \ - size_t offset = (groupname##__next + align_mask) & ~align_mask;\ - size_t size = groupname##_##name##__sz; \ - groupname##__next = offset + size; \ - offset; \ + size_t groupname##_##name##__sz = array_size(n, sizeof(type)); \ + size_t groupname##_##name##__offset = ({ \ + size_t offset = 0; \ + if (groupname##__next != SIZE_MAX) { \ + size_t align_mask = __alignof__(type) - 1; \ + size_t offset = (groupname##__next + align_mask) \ + & ~align_mask; \ + if (check_add_overflow(offset, groupname##_##name##__sz,\ + &groupname##__next)) { \ + groupname##__next = SIZE_MAX; \ + offset = 0; \ + } \ + } \ + offset; \ }) #define vla_ptr(ptr, groupname, name) \ |