diff options
| author | Rolf Eike Beer <eb@emlix.com> | 2022-10-19 09:32:35 +0200 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2022-10-25 15:19:48 -0700 |
| commit | bfb4a2b95875a47a01234f2de113ec089d524e71 (patch) | |
| tree | 5504d985271fe5c15cb193423169553bdc4acd3b /fs/exec.c | |
| parent | 8f6e3f9e5a0f58e458a348b7e36af11d0e9702af (diff) | |
| download | lwn-bfb4a2b95875a47a01234f2de113ec089d524e71.tar.gz lwn-bfb4a2b95875a47a01234f2de113ec089d524e71.zip | |
exec: simplify initial stack size expansion
I had a hard time trying to understand completely why it is using vm_end in
one side of the expression and vm_start in the other one, and using
something in the "if" clause that is not an exact copy of what is used
below. The whole point is that the stack_size variable that was used in the
"if" clause is the difference between vm_start and vm_end, which is not far
away but makes this thing harder to read than it must be.
Signed-off-by: Rolf Eike Beer <eb@emlix.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/2017429.gqNitNVd0C@mobilepool36.emlix.com
Diffstat (limited to 'fs/exec.c')
| -rw-r--r-- | fs/exec.c | 13 |
1 files changed, 5 insertions, 8 deletions
diff --git a/fs/exec.c b/fs/exec.c index 1644bf10fb9d..9585bc1bc970 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -843,16 +843,13 @@ int setup_arg_pages(struct linux_binprm *bprm, * will align it up. */ rlim_stack = bprm->rlim_stack.rlim_cur & PAGE_MASK; + + stack_expand = min(rlim_stack, stack_size + stack_expand); + #ifdef CONFIG_STACK_GROWSUP - if (stack_size + stack_expand > rlim_stack) - stack_base = vma->vm_start + rlim_stack; - else - stack_base = vma->vm_end + stack_expand; + stack_base = vma->vm_start + stack_expand; #else - if (stack_size + stack_expand > rlim_stack) - stack_base = vma->vm_end - rlim_stack; - else - stack_base = vma->vm_start - stack_expand; + stack_base = vma->vm_end - stack_expand; #endif current->mm->start_stack = bprm->p; ret = expand_stack(vma, stack_base); |