[PATCH] x86_64: Fix access check in ptrace compat
We can't safely directly access an compat_alloc_user_space() pointer with the siginfo copy functions. Bounce it through the stack. Noticed by Al Viro using sparse [ This was only added post 2.6.17, not in any released kernel ] Cc: Al Viro <viro@ftp.linux.org.uk> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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@ -202,17 +202,24 @@ static long ptrace32_siginfo(unsigned request, u32 pid, u32 addr, u32 data)
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{
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int ret;
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compat_siginfo_t *si32 = (compat_siginfo_t *)compat_ptr(data);
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siginfo_t ssi;
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siginfo_t *si = compat_alloc_user_space(sizeof(siginfo_t));
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if (request == PTRACE_SETSIGINFO) {
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ret = copy_siginfo_from_user32(si, si32);
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memset(&ssi, 0, sizeof(siginfo_t));
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ret = copy_siginfo_from_user32(&ssi, si32);
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if (ret)
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return ret;
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if (copy_to_user(si, &ssi, sizeof(siginfo_t)))
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return -EFAULT;
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}
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ret = sys_ptrace(request, pid, addr, (unsigned long)si);
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if (ret)
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return ret;
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if (request == PTRACE_GETSIGINFO)
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ret = copy_siginfo_to_user32(si32, si);
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if (request == PTRACE_GETSIGINFO) {
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if (copy_from_user(&ssi, si, sizeof(siginfo_t)))
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return -EFAULT;
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ret = copy_siginfo_to_user32(si32, &ssi);
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}
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return ret;
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}
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