git: 486dfbb67e09 - main - kld: Reject kernel modules with PT_LOAD segments where filesz > memsz
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Date: Fri, 31 Jul 2026 17:57:39 UTC
The branch main has been updated by jhb:
URL: https://cgit.FreeBSD.org/src/commit/?id=486dfbb67e093a461a5ebd97f66be9b345f9de77
commit 486dfbb67e093a461a5ebd97f66be9b345f9de77
Author: John Baldwin <jhb@FreeBSD.org>
AuthorDate: 2026-07-31 17:52:42 +0000
Commit: John Baldwin <jhb@FreeBSD.org>
CommitDate: 2026-07-31 17:52:42 +0000
kld: Reject kernel modules with PT_LOAD segments where filesz > memsz
All sorts of places in the ELF loading code assume that filesz <=
memsz, so check that explicitly up front.
Reported by: Jane Smith <thebugfixers@pm.me> (via D57785)
Reviewed by: jrtc27, kib
Differential Revision: https://reviews.freebsd.org/D58542
---
sys/kern/link_elf.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/sys/kern/link_elf.c b/sys/kern/link_elf.c
index 6ab5f4a39580..d7aeefa25433 100644
--- a/sys/kern/link_elf.c
+++ b/sys/kern/link_elf.c
@@ -1110,6 +1110,14 @@ link_elf_load_file(linker_class_t cls, const char* filename,
error = ENOEXEC;
goto out;
}
+
+ if (phdr->p_memsz < phdr->p_filesz) {
+ link_elf_error(filename,
+ "Invalid program header");
+ error = ENOEXEC;
+ goto out;
+ }
+
/*
* XXX: We just trust they come in right order ??
*/