Messages in this thread Patch in this message | | | Date | Fri, 29 Feb 2008 13:57:48 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: [RFC/PATCH] RLIMIT_ARG_MAX |
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On Fri, 29 Feb 2008, Linus Torvalds wrote: > > I do agree that we should at least make the "MAX(stacksize/4, 128k)" > change for backwards compatibility.
How about something like this?
The alternative is to just remove that size check entirely, and depend on get_user_pages() doing the stack limit check (among all the *other* checks it does when it does the acct_stack_growth() thing).
I'd almost prefer that simpler approach, but I don't have any really strong preferences. Anybody?
Linus
--- fs/exec.c | 10 +++++++++- 1 files changed, 9 insertions(+), 1 deletions(-)
diff --git a/fs/exec.c b/fs/exec.c index a44b142..e91f9cb 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -173,8 +173,15 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, return NULL; if (write) { - struct rlimit *rlim = current->signal->rlim; unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; + struct rlimit *rlim; + + /* + * We've historically supported up to 32 pages of argument + * strings even with small stacks + */ + if (size <= 32*PAGE_SIZE) + return page; /* * Limit to 1/4-th the stack size for the argv+env strings. @@ -183,6 +190,7 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, * - the program will have a reasonable amount of stack left * to work from. */ + rlim = current->signal->rlim; if (size > rlim[RLIMIT_STACK].rlim_cur / 4) { put_page(page); return NULL;
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