In NUMMU kernel the value of linux_binprm::p is the offset inside the temporary program arguments array maintained in separate pages in the linux_binprm::page. linux_binprm::exec being a copy of linux_binprm::p thus must be adjusted when that array is copied to the user stack. Without that adjustment the value passed by the NOMMU kernel to the ELF program in the AT_EXECFN entry of the aux array doesn't make any sense and it may break programs that try to access memory pointed to by that entry.
Adjust linux_binprm::exec before the successful return from the transfer_args_to_stack().
Cc: stable@vger.kernel.org Signed-off-by: Max Filippov jcmvbkbc@gmail.com --- fs/exec.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/fs/exec.c b/fs/exec.c index af4fbb61cd53..5ee2545c3e18 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -895,6 +895,7 @@ int transfer_args_to_stack(struct linux_binprm *bprm, goto out; }
+ bprm->exec += *sp_location - MAX_ARG_PAGES * PAGE_SIZE; *sp_location = sp;
out: