[PATCH 2/2] Fix /proc/<pid>/auxv for FDPIC binaries

[Mark Salter]

The FDPIC loader is not storing aux vector info in mm->saved_aux so the aux vectors were
not being exposed through /proc/<pid>/auxv. This patch copies the aux vectors stored on
the user stack into mm->saved_aux so that they may be available through procfs.

Signed-off-by: Mark Salter <msalter@xxxxxxxxxx>
---
 fs/binfmt_elf_fdpic.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index af4c9a4..9651918 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -478,7 +478,7 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 				   struct elf_fdpic_params *interp_params)
 {
 	const struct cred *cred = current_cred();
-	unsigned long sp, csp, nitems;
+	unsigned long sp, csp, nitems, auxv_end;
 	elf_caddr_t __user *argv, *envp;
 	size_t platform_len = 0, len;
 	char *k_platform, *k_base_platform;
@@ -594,6 +594,7 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 	} while (0)
 
 	nr = 0;
+	auxv_end = csp;
 	csp -= 2 * sizeof(unsigned long);
 	NEW_AUX_ENT(AT_NULL, 0);
 	if (k_platform) {
@@ -645,6 +646,10 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
 #endif
 #undef NEW_AUX_ENT
 
+	if (copy_from_user(current->mm->saved_auxv,
+			   (const char __user *) csp, auxv_end - csp))
+		return -EFAULT;
+
 	/* allocate room for argv[] and envv[] */
 	csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);
 	envp = (elf_caddr_t __user *) csp;
-- 
1.8.1.2

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