GNU bug report logs - #79336
[PATCH] df: fix potential null pointer dereference

Previous Next

Full log

View this message in rfc822 format

From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Pádraig Brady <P <at> draigBrady.com>
Cc: tracker <at> debbugs.gnu.org
Subject: bug#79336: closed ([PATCH] df: fix potential null pointer
 dereference)
Date: Sat, 30 Aug 2025 17:53:02 +0000

[Message part 1 (text/plain, inline)]

Your message dated Sat, 30 Aug 2025 18:52:40 +0100
with message-id <e9f534f3-6b66-4c14-98a9-6549788c5a94 <at> draigBrady.com>
and subject line Re: bug#79336: [PATCH] df: fix potential null pointer dereference
has caused the debbugs.gnu.org bug report #79336,
regarding [PATCH] df: fix potential null pointer dereference
to be marked as done.

(If you believe you have received this mail in error, please contact
help-debbugs <at> gnu.org.)


-- 
79336: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=79336
GNU Bug Tracking System
Contact help-debbugs <at> gnu.org with problems

[Message part 2 (message/rfc822, inline)]

From: yubiao hu <huyubiaox <at> gmail.com>
To: bug-coreutils <at> gnu.org
Subject: [PATCH] df: fix potential null pointer dereference
Date: Fri, 29 Aug 2025 09:45:46 +0800

* src/df.c (get_dev): Fix potential null pointer dereference
- Avoid dereferencing stat_file when both device and
 mount_point are NULL
- Handle allocation failure for cell when mount_point
 is NULL

---
 src/df.c | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/src/df.c b/src/df.c
index fe2e0e3..f60319c 100644
--- a/src/df.c
+++ b/src/df.c
@@ -1050,7 +1050,7 @@ get_dev (char const *device, char const
*mount_point, char const *file,
         }
       else
         {
-          error (0, errno, "%s", quotef (stat_file));
+          error (0, errno, "%s", quotef (stat_file ? stat_file : "-"));
           exit_status = EXIT_FAILURE;
           return;
         }
@@ -1215,17 +1215,23 @@ get_dev (char const *device, char const
*mount_point, char const *file,
           break;

         case TARGET_FIELD:
+          {
+            if (! mount_point) {
+              cell = xstrdup ("-");
+              break;
+            }
 #ifdef HIDE_AUTOMOUNT_PREFIX
-          /* Don't print the first directory name in MOUNT_POINT if it's an
-             artifact of an automounter.  This is a bit too aggressive to be
-             the default.  */
-          if (STRNCMP_LIT (mount_point, "/auto/") == 0)
-            mount_point += 5;
-          else if (STRNCMP_LIT (mount_point, "/tmp_mnt/") == 0)
-            mount_point += 8;
+            /* Don't print the first directory name in MOUNT_POINT if it's an
+              artifact of an automounter.  This is a bit too aggressive to be
+              the default.  */
+            if (STRNCMP_LIT (mount_point, "/auto/") == 0)
+              mount_point += 5;
+            else if (STRNCMP_LIT (mount_point, "/tmp_mnt/") == 0)
+              mount_point += 8;
 #endif
-          cell = xstrdup (mount_point);
-          break;
+            cell = xstrdup (mount_point);
+            break;
+          }

         case INVALID_FIELD:
         default:
-- 
2.33.0

[Message part 3 (message/rfc822, inline)]

From: Pádraig Brady <P <at> draigBrady.com>
To: yubiao hu <huyubiaox <at> gmail.com>, 79336-done <at> debbugs.gnu.org
Subject: Re: bug#79336: [PATCH] df: fix potential null pointer dereference
Date: Sat, 30 Aug 2025 18:52:40 +0100

[Message part 4 (text/plain, inline)]

On 29/08/2025 02:45, yubiao hu wrote:
> * src/df.c (get_dev): Fix potential null pointer dereference
> - Avoid dereferencing stat_file when both device and
>   mount_point are NULL
> - Handle allocation failure for cell when mount_point
>   is NULL

These are valid concerns.
I also see potential null dereferences of device.
The attached patch takes a different approach
by ensuring arguments are initialized earlier.

Marking this as done.

Will push the attached later.

cheers,
Padraig

[df-null-pointers.patch (text/x-patch, attachment)]

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.