git: 0b269737f9ca - main - imgact_elf: handle unaligned phdrs

The branch main has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=0b269737f9ca057826a6c9376c2474b1ae5bc91c

commit 0b269737f9ca057826a6c9376c2474b1ae5bc91c
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2026-06-08 01:22:51 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2026-06-08 17:02:13 +0000

    imgact_elf: handle unaligned phdrs
    
    Althought non-compliant, there are binaries which have the phdrs placed
    unaligned in the image.  Since we have the code to allocate memory for
    off-page phdrs, the same code path can be used to handle unaligned
    phdrs.
    
    Relax the requirement for both the activated image and interpreter.
    
    PR:     295629
    Reviewed by:    emaste, markj, olce
    Sponsored by:   The FreeBSD Foundation
    MFC after:      1 week
    Differential revision:  https://reviews.freebsd.org/D57498
---
 sys/kern/imgact_elf.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/sys/kern/imgact_elf.c b/sys/kern/imgact_elf.c
index b889c4a14866..46908f01097b 100644
--- a/sys/kern/imgact_elf.c
+++ b/sys/kern/imgact_elf.c
@@ -858,12 +858,12 @@ __elfN(load_file)(struct thread *td, const char *file, u_long *addr,
 		goto fail;
 	}
 
-	if (!aligned(imgp->image_header + hdr->e_phoff, Elf_Addr) ||
-	    hdr->e_phnum > __elfN(phnums)) {
+	if (hdr->e_phnum > __elfN(phnums)) {
 		error = ENOEXEC;
 		goto fail;
 	}
-	if (__elfN(phdr_in_zero_page)(hdr)) {
+	if (__elfN(phdr_in_zero_page)(hdr) &&
+	    aligned(imgp->image_header + hdr->e_phoff, Elf_Addr)) {
 		phdr = (const Elf_Phdr *)(imgp->image_header + hdr->e_phoff);
 	} else {
 		VOP_UNLOCK(imgp->vp);
@@ -1157,10 +1157,6 @@ __CONCAT(exec_, __elfN(imgact))(struct image_params *imgp)
 	free_interp = false;
 	m_phdrs = NULL;
 
-	if (!aligned(imgp->image_header + hdr->e_phoff, Elf_Addr)) {
-		uprintf("Unaligned program headers\n");
-		return (ENOEXEC);
-	}
 	if (hdr->e_phoff + hdr->e_phnum * hdr->e_phentsize < hdr->e_phoff) {
 		uprintf("PHDRS wrap\n");
 		return (ENOEXEC);
@@ -1170,7 +1166,8 @@ __CONCAT(exec_, __elfN(imgact))(struct image_params *imgp)
 		    hdr->e_phnum, __elfN(phnums));
 		return (ENOEXEC);
 	}
-	if (__elfN(phdr_in_zero_page)(hdr)) {
+	if (__elfN(phdr_in_zero_page)(hdr) &&
+	    aligned(imgp->image_header + hdr->e_phoff, Elf_Addr)) {
 		phdr = (const Elf_Phdr *)(imgp->image_header + hdr->e_phoff);
 	} else {
 		VOP_UNLOCK(imgp->vp);