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>

arch/arm/include/asm/flat.h

@@ -5,12 +5,31 @@
 #ifndef __ARM_FLAT_H__
 #define __ARM_FLAT_H__
 
+#include <linux/uaccess.h>
+
 #define	flat_argvp_envp_on_stack()		1
 #define	flat_old_ram_flag(flags)		(flags)
 #define	flat_reloc_valid(reloc, size)		((reloc) <= (size))
-#define	flat_get_addr_from_rp(rp, relval, flags, persistent) \
-	({ unsigned long __val; __get_user_unaligned(__val, rp); __val; })
-#define	flat_put_addr_at_rp(rp, val, relval)	__put_user_unaligned(val, rp)
+
+static inline int flat_get_addr_from_rp(u32 __user *rp, u32 relval, u32 flags,
+					u32 *addr, u32 *persistent)
+{
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+	return copy_from_user(addr, rp, 4) ? -EFAULT : 0;
+#else
+	return get_user(*addr, rp);
+#endif
+}
+
+static inline int flat_put_addr_at_rp(u32 __user *rp, u32 addr, u32 rel)
+{
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+	return copy_to_user(rp, &addr, 4) ? -EFAULT : 0;
+#else
+	return put_user(addr, rp);
+#endif
+}
+
 #define	flat_get_relocate_addr(rel)		(rel)
 #define	flat_set_persistent(relval, p)		0
 

arch/blackfin/include/asm/flat.h

@@ -14,23 +14,28 @@
 #define	flat_argvp_envp_on_stack()		0
 #define	flat_old_ram_flag(flags)		(flags)
 
-extern unsigned long bfin_get_addr_from_rp (unsigned long *ptr,
-					unsigned long relval,
-					unsigned long flags,
-					unsigned long *persistent);
+extern unsigned long bfin_get_addr_from_rp (u32 *ptr, u32 relval,
+					u32 flags, u32 *persistent);
 
-extern void bfin_put_addr_at_rp(unsigned long *ptr, unsigned long addr,
-		                unsigned long relval);
+extern void bfin_put_addr_at_rp(u32 *ptr, u32 addr, u32 relval);
 
 /* The amount by which a relocation can exceed the program image limits
    without being regarded as an error.  */
 
 #define	flat_reloc_valid(reloc, size)	((reloc) <= (size))
 
-#define	flat_get_addr_from_rp(rp, relval, flags, persistent)	\
-	bfin_get_addr_from_rp(rp, relval, flags, persistent)
-#define	flat_put_addr_at_rp(rp, val, relval)	\
-	bfin_put_addr_at_rp(rp, val, relval)
+static inline int flat_get_addr_from_rp(u32 __user *rp, u32 relval, u32 flags,
+					u32 *addr, u32 *persistent)
+{
+	*addr = bfin_get_addr_from_rp(rp, relval, flags, persistent);
+	return 0;
+}
+
+static inline int flat_put_addr_at_rp(u32 __user *rp, u32 val, u32 relval)
+{
+	bfin_put_addr_at_rp(rp, val, relval);
+	return 0;
+}
 
 /* Convert a relocation entry into an address.  */
 static inline unsigned long

arch/blackfin/kernel/flat.c

@@ -13,14 +13,14 @@
 #define FLAT_BFIN_RELOC_TYPE_16H_BIT 1
 #define FLAT_BFIN_RELOC_TYPE_32_BIT 2
 
-unsigned long bfin_get_addr_from_rp(unsigned long *ptr,
-		unsigned long relval,
-		unsigned long flags,
-		unsigned long *persistent)
+unsigned long bfin_get_addr_from_rp(u32 *ptr,
+		u32 relval,
+		u32 flags,
+		u32 *persistent)
 {
 	unsigned short *usptr = (unsigned short *)ptr;
 	int type = (relval >> 26) & 7;
-	unsigned long val;
+	u32 val;
 
 	switch (type) {
 	case FLAT_BFIN_RELOC_TYPE_16_BIT:
@@ -59,8 +59,7 @@ EXPORT_SYMBOL(bfin_get_addr_from_rp);
  * Insert the address ADDR into the symbol reference at RP;
  * RELVAL is the raw relocation-table entry from which RP is derived
  */
-void bfin_put_addr_at_rp(unsigned long *ptr, unsigned long addr,
-		unsigned long relval)
+void bfin_put_addr_at_rp(u32 *ptr, u32 addr, u32 relval)
 {
 	unsigned short *usptr = (unsigned short *)ptr;
 	int type = (relval >> 26) & 7;

arch/c6x/include/asm/flat.h

@@ -1,11 +1,22 @@
 #ifndef __ASM_C6X_FLAT_H
 #define __ASM_C6X_FLAT_H
 
+#include <asm/unaligned.h>
+
 #define flat_argvp_envp_on_stack()			0
 #define flat_old_ram_flag(flags)			(flags)
 #define flat_reloc_valid(reloc, size)			((reloc) <= (size))
-#define flat_get_addr_from_rp(rp, relval, flags, p)	get_unaligned(rp)
-#define flat_put_addr_at_rp(rp, val, relval)		put_unaligned(val, rp)
+static inline int flat_get_addr_from_rp(u32 __user *rp, u32 relval, u32 flags,
+					u32 *addr, u32 *persistent)
+{
+	*addr = get_unaligned((__force u32 *)rp);
+	return 0;
+}
+static inline int flat_put_addr_at_rp(u32 __user *rp, u32 addr, u32 rel)
+{
+	put_unaligned(addr, (__force u32 *)rp);
+	return 0;
+}
 #define flat_get_relocate_addr(rel)			(rel)
 #define flat_set_persistent(relval, p)			0
 

arch/h8300/include/asm/flat.h

@@ -5,6 +5,8 @@
 #ifndef __H8300_FLAT_H__
 #define __H8300_FLAT_H__
 
+#include <asm/unaligned.h>
+
 #define	flat_argvp_envp_on_stack()		1
 #define	flat_old_ram_flag(flags)		1
 #define	flat_reloc_valid(reloc, size)		((reloc) <= (size))
@@ -18,11 +20,21 @@
  */
 
 #define	flat_get_relocate_addr(rel)		(rel & ~0x00000001)
-#define flat_get_addr_from_rp(rp, relval, flags, persistent) \
-	({(void)persistent; \
-		get_unaligned(rp) & (((flags) & FLAT_FLAG_GOTPIC) ?	\
-				     0xffffffff : 0x00ffffff); })
-#define flat_put_addr_at_rp(rp, addr, rel) \
-	put_unaligned(((*(char *)(rp)) << 24) | ((addr) & 0x00ffffff), (rp))
+static inline int flat_get_addr_from_rp(u32 __user *rp, u32 relval, u32 flags,
+					u32 *addr, u32 *persistent)
+{
+	u32 val = get_unaligned((__force u32 *)rp);
+	if (!(flags & FLAT_FLAG_GOTPIC)
+		val &= 0x00ffffff;
+	*addr = val;
+	return 0;
+}
+
+static inline int flat_put_addr_at_rp(u32 __user *rp, u32 addr, u32 rel)
+{
+	u32 *p = (__force u32 *)rp;
+	put_unaligned((addr & 0x00ffffff) | (*(char *)p << 24), p);
+	return 0;
+}
 
 #endif /* __H8300_FLAT_H__ */

arch/m32r/include/asm/flat.h

@@ -17,11 +17,6 @@
 #define	flat_set_persistent(relval, p)		0
 #define	flat_reloc_valid(reloc, size)		\
 	(((reloc) - textlen_for_m32r_lo16_data) <= (size))
-#define flat_get_addr_from_rp(rp, relval, flags, persistent) \
-	m32r_flat_get_addr_from_rp(rp, relval, (text_len) )
-
-#define flat_put_addr_at_rp(rp, addr, relval) \
-	m32r_flat_put_addr_at_rp(rp, addr, relval)
 
 /* Convert a relocation entry into an address.  */
 static inline unsigned long
@@ -57,9 +52,9 @@ flat_get_relocate_addr (unsigned long relval)
 
 static unsigned long textlen_for_m32r_lo16_data = 0;
 
-static inline unsigned long m32r_flat_get_addr_from_rp (unsigned long *rp,
-                                                        unsigned long relval,
-						        unsigned long textlen)
+static inline unsigned long m32r_flat_get_addr_from_rp (u32 *rp,
+                                                        u32 relval,
+						        u32 textlen)
 {
         unsigned int reloc = flat_m32r_get_reloc_type (relval);
 	textlen_for_m32r_lo16_data = 0;
@@ -100,9 +95,7 @@ static inline unsigned long m32r_flat_get_addr_from_rp (unsigned long *rp,
 	return ~0;      /* bogus value */
 }
 
-static inline void m32r_flat_put_addr_at_rp (unsigned long *rp,
-					     unsigned long addr,
-                                             unsigned long relval)
+static inline void flat_put_addr_at_rp(u32 *rp, u32 addr, u32 relval)
 {
         unsigned int reloc = flat_m32r_get_reloc_type (relval);
 	if (reloc & 0xf0) {
@@ -142,4 +135,8 @@ static inline void m32r_flat_put_addr_at_rp (unsigned long *rp,
 	}
 }
 
+// kludge - text_len is a local variable in the only user.
+#define flat_get_addr_from_rp(rp, relval, flags, addr, persistent) \
+	(m32r_flat_get_addr_from_rp(rp, relval, text_len), 0)
+
 #endif /* __ASM_M32R_FLAT_H */

arch/m68k/include/asm/flat.h

@@ -5,12 +5,29 @@
 #ifndef __M68KNOMMU_FLAT_H__
 #define __M68KNOMMU_FLAT_H__
 
+#include <linux/uaccess.h>
+
 #define	flat_argvp_envp_on_stack()		1
 #define	flat_old_ram_flag(flags)		(flags)
 #define	flat_reloc_valid(reloc, size)		((reloc) <= (size))
-#define	flat_get_addr_from_rp(rp, relval, flags, p) \
-	({ unsigned long __val; __get_user_unaligned(__val, rp); __val; })
-#define	flat_put_addr_at_rp(rp, val, relval)	__put_user_unaligned(val, rp)
+static inline int flat_get_addr_from_rp(u32 __user *rp, u32 relval, u32 flags,
+					u32 *addr, u32 *persistent)
+{
+#ifdef CONFIG_CPU_HAS_NO_UNALIGNED
+	return copy_from_user(addr, rp, 4) ? -EFAULT : 0;
+#else
+	return get_user(*addr, rp);
+#endif
+}
+
+static inline int flat_put_addr_at_rp(u32 __user *rp, u32 addr, u32 rel)
+{
+#ifdef CONFIG_CPU_HAS_NO_UNALIGNED
+	return copy_to_user(rp, &addr, 4) ? -EFAULT : 0;
+#else
+	return put_user(addr, rp);
+#endif
+}
 #define	flat_get_relocate_addr(rel)		(rel)
 
 static inline int flat_set_persistent(unsigned long relval,

arch/microblaze/include/asm/flat.h

@@ -32,29 +32,27 @@
  * reference
  */
 
-static inline unsigned long
-flat_get_addr_from_rp(unsigned long *rp, unsigned long relval,
-			unsigned long flags, unsigned long *persistent)
+static inline int flat_get_addr_from_rp(u32 __user *rp, u32 relval, u32 flags,
+					u32 *addr, u32 *persistent)
 {
-	unsigned long addr;
-	(void)flags;
+	u32 *p = (__force u32 *)rp;
 
 	/* Is it a split 64/32 reference? */
 	if (relval & 0x80000000) {
 		/* Grab the two halves of the reference */
-		unsigned long val_hi, val_lo;
+		u32 val_hi, val_lo;
 
-		val_hi = get_unaligned(rp);
-		val_lo = get_unaligned(rp+1);
+		val_hi = get_unaligned(p);
+		val_lo = get_unaligned(p+1);
 
 		/* Crack the address out */
-		addr = ((val_hi & 0xffff) << 16) + (val_lo & 0xffff);
+		*addr = ((val_hi & 0xffff) << 16) + (val_lo & 0xffff);
 	} else {
 		/* Get the address straight out */
-		addr = get_unaligned(rp);
+		*addr = get_unaligned(p);
 	}
 
-	return addr;
+	return 0;
 }
 
 /*
@@ -63,25 +61,27 @@ flat_get_addr_from_rp(unsigned long *rp, unsigned long relval,
  */
 
 static inline void
-flat_put_addr_at_rp(unsigned long *rp, unsigned long addr, unsigned long relval)
+flat_put_addr_at_rp(u32 __user *rp, u32 addr, u32 relval)
 {
+	u32 *p = (__force u32 *)rp;
 	/* Is this a split 64/32 reloc? */
 	if (relval & 0x80000000) {
 		/* Get the two "halves" */
-		unsigned long val_hi = get_unaligned(rp);
-		unsigned long val_lo = get_unaligned(rp + 1);
+		unsigned long val_hi = get_unaligned(p);
+		unsigned long val_lo = get_unaligned(p + 1);
 
 		/* insert the address */
 		val_hi = (val_hi & 0xffff0000) | addr >> 16;
 		val_lo = (val_lo & 0xffff0000) | (addr & 0xffff);
 
 		/* store the two halves back into memory */
-		put_unaligned(val_hi, rp);
-		put_unaligned(val_lo, rp+1);
+		put_unaligned(val_hi, p);
+		put_unaligned(val_lo, p+1);
 	} else {
 		/* Put it straight in, no messing around */
-		put_unaligned(addr, rp);
+		put_unaligned(addr, p);
 	}
+	return 0;
 }
 
 #define	flat_get_relocate_addr(rel)	(rel & 0x7fffffff)

arch/sh/include/asm/flat.h

@@ -12,11 +12,22 @@
 #ifndef __ASM_SH_FLAT_H
 #define __ASM_SH_FLAT_H
 
+#include <asm/unaligned.h>
+
 #define	flat_argvp_envp_on_stack()		0
 #define	flat_old_ram_flag(flags)		(flags)
 #define	flat_reloc_valid(reloc, size)		((reloc) <= (size))
-#define	flat_get_addr_from_rp(rp, relval, flags, p)	get_unaligned(rp)
-#define	flat_put_addr_at_rp(rp, val, relval)	put_unaligned(val,rp)
+static inline int flat_get_addr_from_rp(u32 __user *rp, u32 relval, u32 flags,
+					u32 *addr, u32 *persistent)
+{
+	*addr = get_unaligned((__force u32 *)rp);
+	return 0;
+}
+static inline int flat_put_addr_at_rp(u32 __user *rp, u32 addr, u32 rel)
+{
+	put_unaligned(addr, (__force u32 *)rp);
+	return 0;
+}
 #define	flat_get_relocate_addr(rel)		(rel)
 #define	flat_set_persistent(relval, p)		({ (void)p; 0; })
 

arch/xtensa/include/asm/flat.h

@@ -1,11 +1,22 @@
 #ifndef __ASM_XTENSA_FLAT_H
 #define __ASM_XTENSA_FLAT_H
 
+#include <asm/unaligned.h>
+
 #define flat_argvp_envp_on_stack()			0
 #define flat_old_ram_flag(flags)			(flags)
 #define flat_reloc_valid(reloc, size)			((reloc) <= (size))
-#define flat_get_addr_from_rp(rp, relval, flags, p)	get_unaligned(rp)
-#define flat_put_addr_at_rp(rp, val, relval	)	put_unaligned(val, rp)
+static inline int flat_get_addr_from_rp(u32 __user *rp, u32 relval, u32 flags,
+					u32 *addr, u32 *persistent)
+{
+	*addr = get_unaligned((__force u32 *)rp);
+	return 0;
+}
+static inline int flat_put_addr_at_rp(u32 __user *rp, u32 addr, u32 rel)
+{
+	put_unaligned(addr, (__force u32 *)rp);
+	return 0;
+}
 #define flat_get_relocate_addr(rel)			(rel)
 #define flat_set_persistent(relval, p)			0
 

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);

include/linux/flat.h

@@ -9,8 +9,8 @@
 #ifndef _LINUX_FLAT_H
 #define _LINUX_FLAT_H
 
-#include <asm/flat.h>
 #include <uapi/linux/flat.h>
+#include <asm/flat.h>
 
 /*
  * While it would be nice to keep this header clean,  users of older