Date: Sat, 2 Jun 2001 05:28:41 -0700 (PDT) From: jyliu@163.net To: freebsd-gnats-submit@FreeBSD.org Subject: kern/27835: execve() doesn't conform to execve(2) spec in syscall manual Message-ID: <200106021228.f52CSfn65138@freefall.freebsd.org>
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>Number: 27835
>Category: kern
>Synopsis: execve() doesn't conform to execve(2) spec in syscall manual
>Confidential: no
>Severity: non-critical
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Sat Jun 02 05:30:01 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator: Jiangyi Liu
>Release: 4.3-STABLE
>Organization:
>Environment:
FreeBSD fatcow.home 4.3-STABLE FreeBSD 4.3-STABLE #2: Sat Jun 2 19:59:52 CST 2001 jyliu@fatcow.home:/usr/src/sys/compile/FATCOW i386
>Description:
According to execve(2), the argument argv is a pointer to a
null-terminated array of character pointers to null-terminated
character strings and at least one argument must be presented
in the array.
But execve("/bin/sh", NULL, NULL) runs without any error.
Maybe it's harmless, but it doesn't conform to the syscall spec
and it may tempt people to write non-portable code.
>How-To-Repeat:
Run the following code. Notice it runs without the expected error, EINVAL.
#include <unistd.h>
int main()
{
if(execve("/bin/sh", NULL, NULL) < 0)
perror("execve");
}
>Fix:
Following is an attampt to fix this problem. The part of ERRORS
in execve(2) manual need to be updated for a new entry, EINVAL.
---begins here---
--- kern_exec.c.orig Sat Jun 2 12:32:29 2001
+++ kern_exec.c Sat Jun 2 19:58:48 2001
@@ -548,7 +548,13 @@
imgp->argc++;
} while ((argp = (caddr_t) (intptr_t) fuword(argv++)));
}
- }
+ }
+
+ /*
+ * at least one argument must be presented in argv
+ */
+ if (!imgp->argc)
+ return (EINVAL);
imgp->endargs = imgp->stringp;
---ends here---
>Release-Note:
>Audit-Trail:
>Unformatted:
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