From: Heather McIntyre <hsm2@rice.edu>
Date: Fri, 12 Jul 2024 22:32:34 +0000 (-0400)
Subject: libelf: Fix deadlock in elf_cntl
X-Git-Tag: elfutils-0.192~48
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=97b72c00603d1221c69ed22a8345817dde1685f3;p=thirdparty%2Felfutils.git

libelf: Fix deadlock in elf_cntl

        * libelf/elf_cntl.c (elf_cntl): Move rwlock_wrlock, rwlock_unlock,
        inside case switch statements.  Remove unnecessary early return.

Signed-off-by: Heather S. McIntyre <hsm2@rice.edu>
Signed-off-by: Aaron Merey <amerey@redhat.com>
Signed-off-by: Mark Wielaard <mark@klomp.org>
---

diff --git a/libelf/elf_cntl.c b/libelf/elf_cntl.c
index 04aa9132..da4ea999 100644
--- a/libelf/elf_cntl.c
+++ b/libelf/elf_cntl.c
@@ -42,19 +42,11 @@ elf_cntl (Elf *elf, Elf_Cmd cmd)
   if (elf == NULL)
     return -1;
 
-  if (elf->fildes == -1)
-    {
-      __libelf_seterrno (ELF_E_INVALID_HANDLE);
-      return -1;
-    }
-
-  rwlock_wrlock (elf->lock);
-
   switch (cmd)
     {
     case ELF_C_FDREAD:
       /* If not all of the file is in the memory read it now.  */
-      if (elf->map_address == NULL && __libelf_readall (elf) == NULL)
+      if (__libelf_readall (elf) == NULL)
 	{
 	  /* We were not able to read everything.  */
 	  result = -1;
@@ -64,7 +56,9 @@ elf_cntl (Elf *elf, Elf_Cmd cmd)
 
     case ELF_C_FDDONE:
       /* Mark the file descriptor as not usable.  */
+      rwlock_wrlock (elf->lock);
       elf->fildes = -1;
+      rwlock_unlock (elf->lock);
       break;
 
     default:
@@ -73,7 +67,5 @@ elf_cntl (Elf *elf, Elf_Cmd cmd)
       break;
     }
 
-  rwlock_unlock (elf->lock);
-
   return result;
 }