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On Fri, Aug 27, 1999 at 04:34:15PM +0200, Manuel Bouyer wrote:
> Ok, here's another diff which takes in account different objections I've got.
> Now a core file is erased, or a symlink is followed only if the effective
> user id is the same as the existing file or symlink.
> I hope this one will make every one happy :)
> If noone object I'll commit this tomorow.
> 
> --
> Manuel Bouyer, LIP6, Universite Paris VI.           Manuel.Bouyer@lip6.fr
> --

Arg, I did it again, I forgot to attach the diff !

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Index: kern_sig.c
===================================================================
RCS file: /cvsroot/syssrc/sys/kern/kern_sig.c,v
retrieving revision 1.92
diff -u -r1.92 kern_sig.c
--- kern_sig.c	1999/07/25 06:30:34	1.92
+++ kern_sig.c	1999/08/27 14:18:59
@@ -1263,6 +1263,7 @@
 	register struct ucred *cred = p->p_cred->pc_ucred;
 	struct nameidata nd;
 	struct vattr vattr;
+	struct stat stat;
 	int error, error1;
 	char name[MAXCOMLEN+6];		/* progname.core */
 	struct core core;
@@ -1297,6 +1298,22 @@
 		sprintf(name, "core");
 	else
 		sprintf(name, "%s.core", p->p_comm);
+	NDINIT(&nd, LOOKUP, NOFOLLOW | LOCKLEAF, UIO_SYSSPACE, name, p);
+	error = namei(&nd);
+	if (error == 0) {
+		error = vn_stat(nd.ni_vp, &stat, p);
+		vput(nd.ni_vp);
+		if (error)
+			return error;
+		/*
+		 * Don't dump if the owner of the
+		 * process is not the one owning the existing file/symlink
+		 */
+		if (stat.st_uid != p->p_ucred->cr_uid)
+			return EINVAL;
+	} else if (error != ENOENT)
+		return error;
+	/* Now follow symlink if there is one */
 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, name, p);
 	error = vn_open(&nd, O_CREAT | FWRITE, S_IRUSR | S_IWUSR);
 	if (error)

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