From: Aleksei Vetrov <vvvvvv@google.com>
Date: Wed, 25 Jan 2023 14:16:57 +0000 (+0000)
Subject: libdwfl: add check for elf_memory return value
X-Git-Tag: elfutils-0.189~36
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=8d77b719333fb47722a5684f9e0d3f23257346d3;p=thirdparty%2Felfutils.git

libdwfl: add check for elf_memory return value

elf_memory call in __libdw_open_elf_memory can return NULL. It was not
checked and led to the null pointer dereference.

Signed-off-by: Aleksei Vetrov <vvvvvv@google.com>
---

diff --git a/libdwfl/open.c b/libdwfl/open.c
index b97ff0162..d0f357edd 100644
--- a/libdwfl/open.c
+++ b/libdwfl/open.c
@@ -211,6 +211,10 @@ __libdw_open_elf_memory (char *data, size_t size, Elf **elfp, bool archive_ok)
      won't work.  */
   int fd = -1;
   *elfp = elf_memory (data, size);
+  if (unlikely(*elfp == NULL))
+    {
+      return DWFL_E_LIBELF;
+    }
   /* Allow using this ELF as reference for subsequent elf_begin calls.  */
   (*elfp)->cmd = ELF_C_READ_MMAP_PRIVATE;
   return libdw_open_elf (&fd, elfp, false, archive_ok, true, false, true);
diff --git a/tests/dwfl-report-offline-memory.c b/tests/dwfl-report-offline-memory.c
index e6cb0a51f..b3b4d9bd1 100644
--- a/tests/dwfl-report-offline-memory.c
+++ b/tests/dwfl-report-offline-memory.c
@@ -77,8 +77,13 @@ main (int argc, char **argv)
   Dwfl *dwfl = dwfl_begin (&offline_callbacks);
   assert (dwfl != NULL);
 
-  Dwfl_Module *mod =
-      dwfl_report_offline_memory (dwfl, argv[1], argv[1], data, size);
+  Dwfl_Module *mod;
+
+  /* Check error handling by suppling zero data */
+  mod = dwfl_report_offline_memory(dwfl, argv[1], argv[1], NULL, 0);
+  assert(mod == NULL);
+
+  mod = dwfl_report_offline_memory(dwfl, argv[1], argv[1], data, size);
   assert (mod != NULL);
   dwfl_report_end (dwfl, NULL, NULL);