diff options
author | Brooke Basile <brookebasile@gmail.com> | 2020-08-25 09:05:08 -0400 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-09-03 11:22:33 +0200 |
commit | fc0019fac05f97068f0b7d53bb4c081ae2a23e95 (patch) | |
tree | edef9387f71f51484390731f8e521f0f4882597b /drivers/usb | |
parent | 80459b71e2ce64b39eafc2422212e4c99066d118 (diff) |
USB: gadget: u_f: add overflow checks to VLA macros
commit b1cd1b65afba95971fa457dfdb2c941c60d38c5b 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>
Diffstat (limited to 'drivers/usb')
-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 2f03334c6874..a0b3e4989cd5 100644 --- a/drivers/usb/gadget/u_f.h +++ b/drivers/usb/gadget/u_f.h @@ -17,6 +17,7 @@ #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 @@ -24,21 +25,36 @@ #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) \ |