53 lines
1.5 KiB
Plaintext
53 lines
1.5 KiB
Plaintext
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From a47739bf3b89432e112d1d2ed9bbdaf1e09d450a Mon Sep 17 00:00:00 2001
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From: Neil Brown <neilb@suse.de>
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Date: Tue, 17 May 2011 14:36:21 +1000
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Subject: [PATCH] Remove risk of nfs_addmntent corrupting mtab
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nfs_addmntent is used to append directly to /etc/mtab.
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If the write partially fail, e.g. due to RLIMIT_FSIZE,
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truncate back to original size and return an error.
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See also https://bugzilla.redhat.com/show_bug.cgi?id=697975
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(CVE-2011-1749) CVE-2011-1749 nfs-utils: mount.nfs fails to anticipate RLIMIT_FSIZE
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Signed-off-by: NeilBrown <neilb@suse.de>
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---
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support/nfs/nfs_mntent.c | 9 +++++++++
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1 file changed, 9 insertions(+)
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--- nfs-utils-1.2.1.orig/support/nfs/nfs_mntent.c
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+++ nfs-utils-1.2.1/support/nfs/nfs_mntent.c
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@@ -12,6 +12,7 @@
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#include <string.h> /* for index */
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#include <ctype.h> /* for isdigit */
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#include <sys/stat.h> /* for umask */
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+#include <unistd.h> /* for ftruncate */
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#include "nfs_mntent.h"
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#include "nls.h"
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@@ -127,9 +128,11 @@ int
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nfs_addmntent (mntFILE *mfp, struct mntent *mnt) {
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char *m1, *m2, *m3, *m4;
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int res;
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+ off_t length;
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if (fseek (mfp->mntent_fp, 0, SEEK_END))
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return 1; /* failure */
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+ length = ftell(mfp->mntent_fp);
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m1 = mangle(mnt->mnt_fsname);
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m2 = mangle(mnt->mnt_dir);
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@@ -143,6 +146,12 @@ nfs_addmntent (mntFILE *mfp, struct mnte
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free(m2);
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free(m3);
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free(m4);
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+ if (res >= 0)
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+ res = fflush(mfp->mntent_fp);
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+ if (res < 0)
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+ /* Avoid leaving a corrupt mtab file */
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+ ftruncate(fileno(mfp->mntent_fp), length);
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+
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return (res < 0) ? 1 : 0;
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}
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