binfmt_flat: flat_{get,put}_addr_from_rp() should be able to fail

on MMU targets EFAULT is possible here.  Make both return 0 or error,
passing what used to be the return value of flat_get_addr_from_rp()
by reference.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 22 insertions, 17 deletions

diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index 2edcefc..69ec23d 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -422,9 +422,9 @@ static int load_flat_file(struct linux_binprm *bprm,
 {
 	struct flat_hdr *hdr;
 	unsigned long textpos, datapos, realdatastart;
-	unsigned long text_len, data_len, bss_len, stack_len, full_data, flags;
+	u32 text_len, data_len, bss_len, stack_len, full_data, flags;
 	unsigned long len, memp, memp_size, extra, rlim;
-	unsigned long __user *reloc, *rp;
+	u32 __user *reloc, *rp;
 	struct inode *inode;
 	int i, rev, relocs;
 	loff_t fpos;
@@ -596,13 +596,13 @@ static int load_flat_file(struct linux_binprm *bprm,
 			goto err;
 		}
 
-		reloc = (unsigned long __user *)
+		reloc = (u32 __user *)
 			(datapos + (ntohl(hdr->reloc_start) - text_len));
 		memp = realdatastart;
 		memp_size = len;
 	} else {
 
-		len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
+		len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(u32);
 		len = PAGE_ALIGN(len);
 		textpos = vm_mmap(NULL, 0, len,
 			PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0);
@@ -618,10 +618,10 @@ static int load_flat_file(struct linux_binprm *bprm,
 
 		realdatastart = textpos + ntohl(hdr->data_start);
 		datapos = ALIGN(realdatastart +
-				MAX_SHARED_LIBS * sizeof(unsigned long),
+				MAX_SHARED_LIBS * sizeof(u32),
 				FLAT_DATA_ALIGN);
 
-		reloc = (unsigned long __user *)
+		reloc = (u32 __user *)
 			(datapos + (ntohl(hdr->reloc_start) - text_len));
 		memp = textpos;
 		memp_size = len;
@@ -694,7 +694,7 @@ static int load_flat_file(struct linux_binprm *bprm,
 			ret = result;
 			pr_err("Unable to read code+data+bss, errno %d\n", ret);
 			vm_munmap(textpos, text_len + data_len + extra +
-				MAX_SHARED_LIBS * sizeof(unsigned long));
+				MAX_SHARED_LIBS * sizeof(u32));
 			goto err;
 		}
 	}
@@ -754,8 +754,8 @@ static int load_flat_file(struct linux_binprm *bprm,
 	 * image.
 	 */
 	if (flags & FLAT_FLAG_GOTPIC) {
-		for (rp = (unsigned long __user *)datapos; ; rp++) {
-			unsigned long addr, rp_val;
+		for (rp = (u32 __user *)datapos; ; rp++) {
+			u32 addr, rp_val;
 			if (get_user(rp_val, rp))
 				return -EFAULT;
 			if (rp_val == 0xffffffff)
@@ -784,9 +784,9 @@ static int load_flat_file(struct linux_binprm *bprm,
 	 * __start to address 4 so that is okay).
 	 */
 	if (rev > OLD_FLAT_VERSION) {
-		unsigned long __maybe_unused persistent = 0;
+		u32 __maybe_unused persistent = 0;
 		for (i = 0; i < relocs; i++) {
-			unsigned long addr, relval;
+			u32 addr, relval;
 
 			/*
 			 * Get the address of the pointer to be
@@ -799,15 +799,18 @@ static int load_flat_file(struct linux_binprm *bprm,
 			if (flat_set_persistent(relval, &persistent))
 				continue;
 			addr = flat_get_relocate_addr(relval);
-			rp = (unsigned long __user *)calc_reloc(addr, libinfo, id, 1);
-			if (rp == (unsigned long __user *)RELOC_FAILED) {
+			rp = (u32 __user *)calc_reloc(addr, libinfo, id, 1);
+			if (rp == (u32 __user *)RELOC_FAILED) {
 				ret = -ENOEXEC;
 				goto err;
 			}
 
 			/* Get the pointer's value.  */
-			addr = flat_get_addr_from_rp(rp, relval, flags,
-							&persistent);
+			ret = flat_get_addr_from_rp(rp, relval, flags,
+							&addr, &persistent);
+			if (unlikely(ret))
+				goto err;
+
 			if (addr != 0) {
 				/*
 				 * Do the relocation.  PIC relocs in the data section are
@@ -822,12 +825,14 @@ static int load_flat_file(struct linux_binprm *bprm,
 				}
 
 				/* Write back the relocated pointer.  */
-				flat_put_addr_at_rp(rp, addr, relval);
+				ret = flat_put_addr_at_rp(rp, addr, relval);
+				if (unlikely(ret))
+					goto err;
 			}
 		}
 	} else {
 		for (i = 0; i < relocs; i++) {
-			unsigned long relval;
+			u32 relval;
 			if (get_user(relval, reloc + i))
 				return -EFAULT;
 			relval = ntohl(relval);