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authorLaurent Vivier <laurent@vivier.eu>2020-01-28 14:25:39 +0100
committerHelge Deller <deller@gmx.de>2021-02-15 18:28:30 +0100
commit2347961b11d4079deace3c81dceed460c08a8fc1 (patch)
tree95d1d45ad5830c673b6d19b08ede9e9675571926 /fs/binfmt_elf.c
parentb7795074a04669d0a023babf786d29bf67c68783 (diff)
downloadlinux-2347961b11d4079deace3c81dceed460c08a8fc1.tar.gz
binfmt_misc: pass binfmt_misc flags to the interpreter
It can be useful to the interpreter to know which flags are in use.

For instance, knowing if the preserve-argv[0] is in use would
allow to skip the pathname argument.

This patch uses an unused auxiliary vector, AT_FLAGS, to add a
flag to inform interpreter if the preserve-argv[0] is enabled.

Note by Helge Deller:
The real-world user of this patch is qemu-user, which needs to know
if it has to preserve the argv[0]. See Debian bug #970460.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: YunQiang Su <ysu@wavecomp.com>
URL: http://bugs.debian.org/970460
Signed-off-by: Helge Deller <deller@gmx.de>
Diffstat (limited to 'fs/binfmt_elf.c')
-rw-r--r--fs/binfmt_elf.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 950bc177238a..11fb68e68f65 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -186,6 +186,7 @@ create_elf_tables(struct linux_binprm *bprm, const struct elfhdr *exec,
 	unsigned char k_rand_bytes[16];
 	int items;
 	elf_addr_t *elf_info;
+	elf_addr_t flags = 0;
 	int ei_index;
 	const struct cred *cred = current_cred();
 	struct vm_area_struct *vma;
@@ -260,7 +261,9 @@ create_elf_tables(struct linux_binprm *bprm, const struct elfhdr *exec,
 	NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr));
 	NEW_AUX_ENT(AT_PHNUM, exec->e_phnum);
 	NEW_AUX_ENT(AT_BASE, interp_load_addr);
-	NEW_AUX_ENT(AT_FLAGS, 0);
+	if (bprm->interp_flags & BINPRM_FLAGS_PRESERVE_ARGV0)
+		flags |= AT_FLAGS_PRESERVE_ARGV0;
+	NEW_AUX_ENT(AT_FLAGS, flags);
 	NEW_AUX_ENT(AT_ENTRY, e_entry);
 	NEW_AUX_ENT(AT_UID, from_kuid_munged(cred->user_ns, cred->uid));
 	NEW_AUX_ENT(AT_EUID, from_kuid_munged(cred->user_ns, cred->euid));