[glibc] elf: ldconfig should skip temporary files created by package managers

[glibc] elf: ldconfig should skip temporary files created by package managers

[Florian Weimer]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=2aa0974d2573441bffd596b07bff8698b1f2f18c

commit 2aa0974d2573441bffd596b07bff8698b1f2f18c
Author: Florian Weimer <fweimer@redhat.com>
Date:   Fri Oct 20 14:29:50 2023 +0200

    elf: ldconfig should skip temporary files created by package managers
    
    This avoids crashes due to partially written files, after a package
    update is interrupted.
    
    Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

Diff:
---
 NEWS           |  4 +++-
 elf/ldconfig.c | 39 +++++++++++++++++++++++++++------------
 2 files changed, 30 insertions(+), 13 deletions(-)

diff --git a/NEWS b/NEWS
index cc4b81f0ac..9432564444 100644
--- a/NEWS
+++ b/NEWS
@@ -40,7 +40,9 @@ Major new features:
 
 Deprecated and removed features, and other changes affecting compatibility:
 
-  [Add deprecations, removals and changes affecting compatibility here]
+* The ldconfig program now skips file names containing ';' or ending in
+  ".tmp", to avoid examining temporary files created by the RPM and dpkg
+  package managers.
 
 Changes to build and runtime requirements:
 
diff --git a/elf/ldconfig.c b/elf/ldconfig.c
index d26eef1fb4..02387a169c 100644
--- a/elf/ldconfig.c
+++ b/elf/ldconfig.c
@@ -661,6 +661,31 @@ struct dlib_entry
   struct dlib_entry *next;
 };
 
+/* Skip some temporary DSO files.  These files may be partially written
+   and lead to ldconfig crashes when examined.  */
+static bool
+skip_dso_based_on_name (const char *name, size_t len)
+{
+  /* Skip temporary files created by the prelink program.  Files with
+     names like these are never really DSOs we want to look at.  */
+  if (len >= sizeof (".#prelink#") - 1)
+    {
+      if (strcmp (name + len - sizeof (".#prelink#") + 1,
+		  ".#prelink#") == 0)
+	return true;
+      if (len >= sizeof (".#prelink#.XXXXXX") - 1
+	  && memcmp (name + len - sizeof (".#prelink#.XXXXXX")
+		     + 1, ".#prelink#.", sizeof (".#prelink#.") - 1) == 0)
+	return true;
+    }
+  /* Skip temporary files created by RPM.  */
+  if (memchr (name, len, ';') != NULL)
+    return true;
+  /* Skip temporary files created by dpkg.  */
+  if (len > 4 && memcmp (name + len - 4, ".tmp", 4) == 0)
+    return true;
+  return false;
+}
 
 static void
 search_dir (const struct dir_entry *entry)
@@ -711,18 +736,8 @@ search_dir (const struct dir_entry *entry)
 	continue;
 
       size_t len = strlen (direntry->d_name);
-      /* Skip temporary files created by the prelink program.  Files with
-	 names like these are never really DSOs we want to look at.  */
-      if (len >= sizeof (".#prelink#") - 1)
-	{
-	  if (strcmp (direntry->d_name + len - sizeof (".#prelink#") + 1,
-		      ".#prelink#") == 0)
-	    continue;
-	  if (len >= sizeof (".#prelink#.XXXXXX") - 1
-	      && memcmp (direntry->d_name + len - sizeof (".#prelink#.XXXXXX")
-			 + 1, ".#prelink#.", sizeof (".#prelink#.") - 1) == 0)
-	    continue;
-	}
+      if (skip_dso_based_on_name (direntry->d_name, len))
+	continue;
       if (asprintf (&file_name, "%s/%s", entry->path, direntry->d_name) < 0)
 	error (EXIT_FAILURE, errno, _("Could not form library path"));
       if (opt_chroot != NULL)