Avoid crashing in LD_DEBUG when program name is unavailable

Resolves: #15465

The program name may be unavailable if the user application tampers
with argc and argv[].  Some parts of the dynamic linker caters for
this while others don't, so this patch consolidates the check and
fallback into a single macro and updates all users.

10 files changed, 15 insertions, 21 deletions

diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index 3f44809..cb17204 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -128,6 +128,11 @@ typedef struct link_map *lookup_t;
    | ((PROT_WRITE | PROT_EXEC) << (PF_W | PF_X) * 4)			      \
    | ((PROT_READ | PROT_WRITE | PROT_EXEC) << ((PF_R | PF_W | PF_X) * 4)))
 
+/* The filename itself, or the main program name, if available.  */
+#define DSO_FILENAME(name) ((name)[0] ? (name)				      \
+			    : (rtld_progname ?: "<main program>"))
+
+#define RTLD_PROGNAME (rtld_progname ?: "<program name unknown>")
 
 /* For the version handling we need an array with only names and their
    hash values.  */
diff --git a/sysdeps/i386/dl-machine.h b/sysdeps/i386/dl-machine.h
index 0b4c467..b6fc805 100644
--- a/sysdeps/i386/dl-machine.h
+++ b/sysdeps/i386/dl-machine.h
@@ -464,8 +464,7 @@ elf_machine_rel (struct link_map *map, const Elf32_Rel *reloc,
 	      strtab = (const char *) D_PTR (map, l_info[DT_STRTAB]);
 	      _dl_error_printf ("\
 %s: Symbol `%s' has different size in shared object, consider re-linking\n",
-				rtld_progname ?: "<program name unknown>",
-				strtab + refsym->st_name);
+				RTLD_PROGNAME, strtab + refsym->st_name);
 	    }
 	  memcpy (reloc_addr_arg, (void *) value,
 		  MIN (sym->st_size, refsym->st_size));
@@ -610,8 +609,7 @@ elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc,
 	      strtab = (const char *) D_PTR (map, l_info[DT_STRTAB]);
 	      _dl_error_printf ("\
 %s: Symbol `%s' has different size in shared object, consider re-linking\n",
-				rtld_progname ?: "<program name unknown>",
-				strtab + refsym->st_name);
+				RTLD_PROGNAME, strtab + refsym->st_name);
 	    }
 	  memcpy (reloc_addr_arg, (void *) value,
 		  MIN (sym->st_size, refsym->st_size));
diff --git a/sysdeps/powerpc/powerpc32/dl-machine.c b/sysdeps/powerpc/powerpc32/dl-machine.c
index bd42fdf..c75c173 100644
--- a/sysdeps/powerpc/powerpc32/dl-machine.c
+++ b/sysdeps/powerpc/powerpc32/dl-machine.c
@@ -510,8 +510,7 @@ __process_machine_rela (struct link_map *map,
 	  strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
 	  _dl_error_printf ("\
 %s: Symbol `%s' has different size in shared object, consider re-linking\n",
-			    rtld_progname ?: "<program name unknown>",
-			    strtab + refsym->st_name);
+			    RTLD_PROGNAME, strtab + refsym->st_name);
 	}
       memcpy (reloc_addr, (char *) finaladdr, MIN (sym->st_size,
 						   refsym->st_size));
diff --git a/sysdeps/powerpc/powerpc64/dl-machine.h b/sysdeps/powerpc/powerpc64/dl-machine.h
index 14ade21..059fdaf 100644
--- a/sysdeps/powerpc/powerpc64/dl-machine.h
+++ b/sysdeps/powerpc/powerpc64/dl-machine.h
@@ -734,8 +734,7 @@ elf_machine_rela (struct link_map *map,
 	  _dl_error_printf ("%s: Symbol `%s' has different size" \
 			    " in shared object," \
 			    " consider re-linking\n",
-			    rtld_progname ?: "<program name unknown>",
-			    strtab + refsym->st_name);
+			    RTLD_PROGNAME, strtab + refsym->st_name);
 	}
       memcpy (reloc_addr_arg, (char *) value,
 	      MIN (sym->st_size, refsym->st_size));
diff --git a/sysdeps/s390/s390-32/dl-machine.h b/sysdeps/s390/s390-32/dl-machine.h
index 544f843..aa8f1a5 100644
--- a/sysdeps/s390/s390-32/dl-machine.h
+++ b/sysdeps/s390/s390-32/dl-machine.h
@@ -383,8 +383,7 @@ elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc,
 	      strtab = (const char *) D_PTR(map,l_info[DT_STRTAB]);
 	      _dl_error_printf ("\
 %s: Symbol `%s' has different size in shared object, consider re-linking\n",
-				rtld_progname ?: "<program name unknown>",
-				strtab + refsym->st_name);
+				RTLD_PROGNAME, strtab + refsym->st_name);
 	    }
 	  memcpy (reloc_addr_arg, (void *) value,
 		  MIN (sym->st_size, refsym->st_size));
diff --git a/sysdeps/s390/s390-64/dl-machine.h b/sysdeps/s390/s390-64/dl-machine.h
index 0504eb6..32f7a2c 100644
--- a/sysdeps/s390/s390-64/dl-machine.h
+++ b/sysdeps/s390/s390-64/dl-machine.h
@@ -361,8 +361,7 @@ elf_machine_rela (struct link_map *map, const Elf64_Rela *reloc,
 	      strtab = (const char *) D_PTR (map,l_info[DT_STRTAB]);
 	      _dl_error_printf ("\
 %s: Symbol `%s' has different size in shared object, consider re-linking\n",
-				rtld_progname ?: "<program name unknown>",
-				strtab + refsym->st_name);
+				RTLD_PROGNAME, strtab + refsym->st_name);
 	    }
 	  memcpy (reloc_addr_arg, (void *) value,
 		  MIN (sym->st_size, refsym->st_size));
diff --git a/sysdeps/sh/dl-machine.h b/sysdeps/sh/dl-machine.h
index 25cd52a..da7b9c1 100644
--- a/sysdeps/sh/dl-machine.h
+++ b/sysdeps/sh/dl-machine.h
@@ -336,8 +336,7 @@ elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc,
 	      strtab = (const char *) D_PTR (map, l_info[DT_STRTAB]);
 	      _dl_error_printf ("\
 %s: Symbol `%s' has different size in shared object, consider re-linking\n",
-				rtld_progname ?: "<program name unknown>",
-				strtab + refsym->st_name);
+				RTLD_PROGNAME, strtab + refsym->st_name);
 	    }
 	  memcpy (reloc_addr_arg, (void *) value,
 		  MIN (sym->st_size, refsym->st_size));
diff --git a/sysdeps/sparc/sparc32/dl-machine.h b/sysdeps/sparc/sparc32/dl-machine.h
index 71e120f..30f9246 100644
--- a/sysdeps/sparc/sparc32/dl-machine.h
+++ b/sysdeps/sparc/sparc32/dl-machine.h
@@ -411,8 +411,7 @@ elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc,
 	  strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
 	  _dl_error_printf ("\
 %s: Symbol `%s' has different size in shared object, consider re-linking\n",
-			    rtld_progname ?: "<program name unknown>",
-			    strtab + refsym->st_name);
+			    RTLD_PROGNAME, strtab + refsym->st_name);
 	}
       memcpy (reloc_addr_arg, (void *) value,
 	      MIN (sym->st_size, refsym->st_size));
diff --git a/sysdeps/sparc/sparc64/dl-machine.h b/sysdeps/sparc/sparc64/dl-machine.h
index d6d20c7..3bce5d1 100644
--- a/sysdeps/sparc/sparc64/dl-machine.h
+++ b/sysdeps/sparc/sparc64/dl-machine.h
@@ -436,8 +436,7 @@ elf_machine_rela (struct link_map *map, const Elf64_Rela *reloc,
 	  strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
 	  _dl_error_printf ("\
 %s: Symbol `%s' has different size in shared object, consider re-linking\n",
-			    rtld_progname ?: "<program name unknown>",
-			    strtab + refsym->st_name);
+			    RTLD_PROGNAME, strtab + refsym->st_name);
 	}
       memcpy (reloc_addr_arg, (void *) value,
 	      MIN (sym->st_size, refsym->st_size));
diff --git a/sysdeps/x86_64/dl-machine.h b/sysdeps/x86_64/dl-machine.h
index 4768c69..116fed1 100644
--- a/sysdeps/x86_64/dl-machine.h
+++ b/sysdeps/x86_64/dl-machine.h
@@ -430,9 +430,7 @@ elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
 #  endif
 	      strtab = (const char *) D_PTR (map, l_info[DT_STRTAB]);
 
-	      _dl_error_printf (fmt,
-				rtld_progname ?: "<program name unknown>",
-				strtab + refsym->st_name);
+	      _dl_error_printf (fmt, RTLD_PROGNAME, strtab + refsym->st_name);
 	    }
 	  break;
 #  ifndef RESOLVE_CONFLICT_FIND_MAP