git: 43d44842aef3 - main - rtld: Fix null-pointer dereference

[Konstantin Belousov]

The branch main has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=43d44842aef3972cc86ce673e84e31f372257b15

commit 43d44842aef3972cc86ce673e84e31f372257b15
Author:     David Chisnall <theraven at FreeBSD.org>
AuthorDate: 2021-02-02 14:06:33 +0000
Commit:     Konstantin Belousov <kib at FreeBSD.org>
CommitDate: 2021-02-02 14:14:16 +0000

    rtld: Fix null-pointer dereference
    
    When a library is opened via fdlopen, it has a null pointer for its path
    and so _rtld_bind can crash as a result of passing the null pointer to
    basename() (which passes it to strrchr(), which doesn't do a null check).
    
    PR:     253081
    Submitted by:   theraven
    MFC after:      1 week
    Differential Revision:  https://reviews.freebsd.org/D28442
---
 libexec/rtld-elf/rtld.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libexec/rtld-elf/rtld.c b/libexec/rtld-elf/rtld.c
index 7b8bfba84d7d..b186bebbfefc 100644
--- a/libexec/rtld-elf/rtld.c
+++ b/libexec/rtld-elf/rtld.c
@@ -894,8 +894,10 @@ _rtld_bind(Obj_Entry *obj, Elf_Size reloff)
 	target = (Elf_Addr)(defobj->relocbase + def->st_value);
 
     dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
-      defobj->strtab + def->st_name, basename(obj->path),
-      (void *)target, basename(defobj->path));
+      defobj->strtab + def->st_name,
+      obj->path == NULL ? NULL : basename(obj->path),
+      (void *)target,
+      defobj->path == NULL ? NULL : basename(defobj->path));
 
     /*
      * Write the new contents for the jmpslot. Note that depending on