Messages in this thread | | | Date | Fri, 25 Feb 2011 18:52:02 +0100 | From | Oleg Nesterov <> | Subject | [PATCH 0/4 RESEND] exec: unify compat/non-compat code |
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On 12/01, Oleg Nesterov wrote: > > On 12/01, Milton Miller wrote: > > > > > +#ifdef CONFIG_COMPAT > > > +int compat_do_execve(char * filename, > > > + compat_uptr_t __user *argv, > > > + compat_uptr_t __user *envp, > > > + struct pt_regs * regs) > > > +{ > > > + return do_execve_common(filename, > > > + (void __user*)argv, (void __user*)envp, > > > > Shouldn't these be compat_ptr(argv)? (makes a difference on s390) > > I'll recheck, but I don't think so. Please note that compat_ptr() > accepts "compat_uptr_t", not "compat_uptr_t *". > > argv should be correct as a pointer to user-space, otherwise the > current code is buggy. For example, compat_do_execve() passes > argv to compat_count() which does get_user(argv) without any > conversion.
So, once again, this should not (and can not) be compat_ptr(argv) afaics.
I don't understand the s390 asm, but compat_wrapper.S:sys32_execve_wrapper looks correct. If not, the current code is already buggy and s390 should be fixed. argv/envp are not compat ptrs, they just point to compat_ data, we should not do any conversion.
I am resending this series unchanged, plus the trivial 5/5 to document acct_arg_size().
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execve code in fs/compat.c must die. It is very hard to maintain this copy-and-paste horror. And the only reason for this duplication is that argv/envp point to char* or compat_uptr_t depending on compat. We can add the trivial helper which hides the difference and unify the code.
Oleg.
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