4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: James Hogan <[email protected]> commit 6ae1756faddefd7494353380ee546dd38c2f97eb upstream. MIPS' struct compat_flock doesn't match the 32-bit struct flock, as it has an extra short __unused before pad[4], which combined with alignment increases the size to 40 bytes compared with struct flock's 36 bytes. Since commit 8c6657cb50cb ("Switch flock copyin/copyout primitives to copy_{from,to}_user()"), put_compat_flock() writes the full compat_flock struct to userland, which results in corruption of the userland word after the struct flock when running 32-bit userlands on 64-bit kernels. This was observed to cause a bus error exception when starting Firefox on Debian 8 (Jessie). Reported-by: Peter Mamonov <[email protected]> Signed-off-by: James Hogan <[email protected]> Tested-by: Peter Mamonov <[email protected]> Cc: Ralf Baechle <[email protected]> Cc: Al Viro <[email protected]> Cc: [email protected] Cc: <[email protected]> # 4.13+ Patchwork: https://patchwork.linux-mips.org/patch/18646/ Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/mips/include/asm/compat.h | 1 - 1 file changed, 1 deletion(-) --- a/arch/mips/include/asm/compat.h +++ b/arch/mips/include/asm/compat.h @@ -86,7 +86,6 @@ struct compat_flock { compat_off_t l_len; s32 l_sysid; compat_pid_t l_pid; - short __unused; s32 pad[4]; };
