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authorMax Filippov <jcmvbkbc@gmail.com>2024-03-20 19:26:07 +0100
committerKees Cook <keescook@chromium.org>2024-03-21 18:05:47 +0100
commit2aea94ac14d1e0a8ae9e34febebe208213ba72f7 (patch)
tree159784ee20375fc7bf45dfda324761fdbfd3615e /fs/exec.c
parentselftests/exec: Convert remaining /bin/sh to /bin/bash (diff)
downloadlinux-2aea94ac14d1e0a8ae9e34febebe208213ba72f7.tar.xz
linux-2aea94ac14d1e0a8ae9e34febebe208213ba72f7.zip
exec: Fix NOMMU linux_binprm::exec in transfer_args_to_stack()
In NOMMU 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> Fixes: b6a2fea39318 ("mm: variable length argument support") Fixes: 5edc2a5123a7 ("binfmt_elf_fdpic: wire up AT_EXECFD, AT_EXECFN, AT_SECURE") Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> Link: https://lore.kernel.org/r/20240320182607.1472887-1-jcmvbkbc@gmail.com Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'fs/exec.c')
-rw-r--r--fs/exec.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/exec.c b/fs/exec.c
index e7d9d6ad980b..f66639820580 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: