[PATCH] commands/file: Fix null dereference in the knetbsd tests

From: Glenn Washburn <development@efficientek.com>
To: grub-devel@gnu.org, Daniel Kiper <dkiper@net-space.pl>
Cc: Lukas Fink <lukas.fink1@gmail.com>,
	Glenn Washburn <development@efficientek.com>
Subject: [PATCH] commands/file: Fix null dereference in the knetbsd tests
Date: Sun,  5 Jan 2025 02:24:11 -0600	[thread overview]
Message-ID: <20250105082411.143880-1-development@efficientek.com> (raw)

From: Lukas Fink <lukas.fink1@gmail.com>

The pointer returned by grub_elf_file() is not checked to verify it is not
null before use. A null pointer may be returned when the given file does
not have a valid ELF header.

Fixes: https://savannah.gnu.org/bugs/?61960
Signed-off-by: Lukas Fink <lukas.fink1@gmail.com>
Signed-off-by: Glenn Washburn <development@efficientek.com>
---
 grub-core/commands/file.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/grub-core/commands/file.c b/grub-core/commands/file.c
index 7c13e976b505..19602d75786b 100644
--- a/grub-core/commands/file.c
+++ b/grub-core/commands/file.c
@@ -306,6 +306,8 @@ grub_cmd_file (grub_extcmd_context_t ctxt, int argc, char **args)
 
 	elf = grub_elf_file (file, file->name);
 
+	if (elf == NULL)
+	  break;
 	if (elf->ehdr.ehdr32.e_type != grub_cpu_to_le16_compile_time (ET_EXEC)
 	    || elf->ehdr.ehdr32.e_ident[EI_DATA] != ELFDATA2LSB)
 	  break;
-- 
2.34.1


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