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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

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Pull more misc uaccess and vfs updates from Al Viro:
 "The rest of the stuff from -next (more uaccess work) + assorted fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  score: traps: Add missing include file to fix build error
  fs/super.c: don't fool lockdep in freeze_super() and thaw_super() paths
  fs/super.c: fix race between freeze_super() and thaw_super()
  overlayfs: Fix setting IOP_XATTR flag
  iov_iter: kernel-doc import_iovec() and rw_copy_check_uvector()
  blackfin: no access_ok() for __copy_{to,from}_user()
  arm64: don't zero in __copy_from_user{,_inatomic}
  arm: don't zero in __copy_from_user_inatomic()/__copy_from_user()
  arc: don't leak bits of kernel stack into coredump
  alpha: get rid of tail-zeroing in __copy_user()
This commit is contained in:
Linus Torvalds 2016-10-14 18:19:05 -07:00
commit b26b5ef5ec
14 changed files with 133 additions and 98 deletions
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9
arch/alpha/include/asm/uaccess.h
View File

@ -396,11 +396,12 @@ copy_to_user(void __user *to, const void *from, long n)
extern inline long
copy_from_user(void *to, const void __user *from, long n)
{
long res = n;
if (likely(__access_ok((unsigned long)from, n, get_fs())))
n = __copy_tofrom_user_nocheck(to, (__force void *)from, n);
else
memset(to, 0, n);
return n;
res = __copy_from_user_inatomic(to, from, n);
if (unlikely(res))
memset(to + (n - res), 0, res);
return res;
}
extern void __do_clear_user(void);

16
arch/alpha/lib/copy_user.S
View File

@ -126,22 +126,8 @@ $65:
bis $31,$31,$0
$41:
$35:
$exitout:
ret $31,($28),1
$exitin:
/* A stupid byte-by-byte zeroing of the rest of the output
buffer. This cures security holes by never leaving
random kernel data around to be copied elsewhere. */
mov $0,$1
$101:
EXO ( ldq_u $2,0($6) )
subq $1,1,$1
mskbl $2,$6,$2
EXO ( stq_u $2,0($6) )
addq $6,1,$6
bgt $1,$101
$exitout:
ret $31,($28),1
.end __copy_user

23
arch/alpha/lib/ev6-copy_user.S
View File

@ -228,33 +228,12 @@ $dirtyentry:
bgt $0,$onebyteloop # U .. .. .. : U L U L
$zerolength:
$exitin:
$exitout: # Destination for exception recovery(?)
nop # .. .. .. E
nop # .. .. E ..
nop # .. E .. ..
ret $31,($28),1 # L0 .. .. .. : L U L U
$exitin:
/* A stupid byte-by-byte zeroing of the rest of the output
buffer. This cures security holes by never leaving
random kernel data around to be copied elsewhere. */
nop
nop
nop
mov $0,$1
$101:
EXO ( stb $31,0($6) ) # L
subq $1,1,$1 # E
addq $6,1,$6 # E
bgt $1,$101 # U
nop
nop
nop
ret $31,($28),1 # L0
.end __copy_user
EXPORT_SYMBOL(__copy_user)

8
arch/arc/kernel/signal.c
View File

@ -107,13 +107,13 @@ static int restore_usr_regs(struct pt_regs *regs, struct rt_sigframe __user *sf)
struct user_regs_struct uregs;
err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
if (!err)
set_current_blocked(&set);
err |= __copy_from_user(&uregs.scratch,
&(sf->uc.uc_mcontext.regs.scratch),
sizeof(sf->uc.uc_mcontext.regs.scratch));
if (err)
return err;
set_current_blocked(&set);
regs->bta = uregs.scratch.bta;
regs->lp_start = uregs.scratch.lp_start;
regs->lp_end = uregs.scratch.lp_end;
@ -138,7 +138,7 @@ static int restore_usr_regs(struct pt_regs *regs, struct rt_sigframe __user *sf)
regs->r0 = uregs.scratch.r0;
regs->sp = uregs.scratch.sp;
return err;
return 0;
}
static inline int is_do_ss_needed(unsigned int magic)

11
arch/arm/include/asm/uaccess.h
View File

@ -533,11 +533,12 @@ __clear_user(void __user *addr, unsigned long n)
static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
{
if (access_ok(VERIFY_READ, from, n))
n = __copy_from_user(to, from, n);
else /* security hole - plug it */
memset(to, 0, n);
return n;
unsigned long res = n;
if (likely(access_ok(VERIFY_READ, from, n)))
res = __copy_from_user(to, from, n);
if (unlikely(res))
memset(to + (n - res), 0, res);
return res;
}
static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)

9
arch/arm/lib/copy_from_user.S
View File

@ -100,12 +100,9 @@ EXPORT_SYMBOL(arm_copy_from_user)
.pushsection .fixup,"ax"
.align 0
copy_abort_preamble
ldmfd sp!, {r1, r2}
sub r3, r0, r1
rsb r1, r3, r2
str r1, [sp]
bl __memzero
ldr r0, [sp], #4
ldmfd sp!, {r1, r2, r3}
sub r0, r0, r1
rsb r0, r0, r2
copy_abort_end
.popsection

10
arch/arm64/include/asm/uaccess.h
View File

@ -278,14 +278,16 @@ static inline unsigned long __must_check __copy_to_user(void __user *to, const v
static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
{
unsigned long res = n;
kasan_check_write(to, n);
if (access_ok(VERIFY_READ, from, n)) {
check_object_size(to, n, false);
n = __arch_copy_from_user(to, from, n);
} else /* security hole - plug it */
memset(to, 0, n);
return n;
res = __arch_copy_from_user(to, from, n);
}
if (unlikely(res))
memset(to + (n - res), 0, res);
return res;
}
static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)

7
arch/arm64/lib/copy_from_user.S
View File

@ -79,11 +79,6 @@ ENDPROC(__arch_copy_from_user)
.section .fixup,"ax"
.align 2
9998:
sub x0, end, dst
9999:
strb wzr, [dst], #1 // zero remaining buffer space
cmp dst, end
b.lo 9999b
9998: sub x0, end, dst // bytes not copied
ret
.previous

32
arch/blackfin/include/asm/uaccess.h
View File

@ -163,18 +163,29 @@ static inline int bad_user_access_length(void)
: "a" (__ptr(ptr))); \
})
#define __copy_from_user(to, from, n) copy_from_user(to, from, n)
#define __copy_to_user(to, from, n) copy_to_user(to, from, n)
#define __copy_to_user_inatomic __copy_to_user
#define __copy_from_user_inatomic __copy_from_user
static inline unsigned long __must_check
__copy_from_user(void *to, const void __user *from, unsigned long n)
{
memcpy(to, (const void __force *)from, n);
return 0;
}
static inline unsigned long __must_check
__copy_to_user(void __user *to, const void *from, unsigned long n)
{
memcpy((void __force *)to, from, n);
SSYNC();
return 0;
}
static inline unsigned long __must_check
copy_from_user(void *to, const void __user *from, unsigned long n)
{
if (likely(access_ok(VERIFY_READ, from, n))) {
memcpy(to, (const void __force *)from, n);
return 0;
}
if (likely(access_ok(VERIFY_READ, from, n)))
return __copy_from_user(to, from, n);
memset(to, 0, n);
return n;
}
@ -182,12 +193,9 @@ copy_from_user(void *to, const void __user *from, unsigned long n)
static inline unsigned long __must_check
copy_to_user(void __user *to, const void *from, unsigned long n)
{
if (access_ok(VERIFY_WRITE, to, n))
memcpy((void __force *)to, from, n);
else
return n;
SSYNC();
return 0;
if (likely(access_ok(VERIFY_WRITE, to, n)))
return __copy_to_user(to, from, n);
return n;
}
/*

1
arch/score/kernel/traps.c
View File

@ -29,6 +29,7 @@
#include <asm/cacheflush.h>
#include <asm/irq.h>
#include <asm/irq_regs.h>
#include <asm/uaccess.h>
unsigned long exception_handlers[32];

11
fs/overlayfs/super.c
View File

@ -1303,6 +1303,12 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
if (!oe)
goto out_put_cred;
sb->s_magic = OVERLAYFS_SUPER_MAGIC;
sb->s_op = &ovl_super_operations;
sb->s_xattr = ovl_xattr_handlers;
sb->s_fs_info = ufs;
sb->s_flags |= MS_POSIXACL | MS_NOREMOTELOCK;
root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR));
if (!root_dentry)
goto out_free_oe;
@ -1326,12 +1332,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
ovl_inode_init(d_inode(root_dentry), realinode, !!upperpath.dentry);
ovl_copyattr(realinode, d_inode(root_dentry));
sb->s_magic = OVERLAYFS_SUPER_MAGIC;
sb->s_op = &ovl_super_operations;
sb->s_xattr = ovl_xattr_handlers;
sb->s_root = root_dentry;
sb->s_fs_info = ufs;
sb->s_flags |= MS_POSIXACL | MS_NOREMOTELOCK;
return 0;

29
fs/read_write.c
View File

@ -730,6 +730,35 @@ static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter,
/* A write operation does a read from user space and vice versa */
#define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ)
/**
* rw_copy_check_uvector() - Copy an array of &struct iovec from userspace
* into the kernel and check that it is valid.
*
* @type: One of %CHECK_IOVEC_ONLY, %READ, or %WRITE.
* @uvector: Pointer to the userspace array.
* @nr_segs: Number of elements in userspace array.
* @fast_segs: Number of elements in @fast_pointer.
* @fast_pointer: Pointer to (usually small on-stack) kernel array.
* @ret_pointer: (output parameter) Pointer to a variable that will point to
* either @fast_pointer, a newly allocated kernel array, or NULL,
* depending on which array was used.
*
* This function copies an array of &struct iovec of @nr_segs from
* userspace into the kernel and checks that each element is valid (e.g.
* it does not point to a kernel address or cause overflow by being too
* large, etc.).
*
* As an optimization, the caller may provide a pointer to a small
* on-stack array in @fast_pointer, typically %UIO_FASTIOV elements long
* (the size of this array, or 0 if unused, should be given in @fast_segs).
*
* @ret_pointer will always point to the array that was used, so the
* caller must take care not to call kfree() on it e.g. in case the
* @fast_pointer array was used and it was allocated on the stack.
*
* Return: The total number of bytes covered by the iovec array on success
* or a negative error code on error.
*/
ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
unsigned long nr_segs, unsigned long fast_segs,
struct iovec *fast_pointer,

43
fs/super.c
View File

@ -1269,25 +1269,34 @@ EXPORT_SYMBOL(__sb_start_write);
static void sb_wait_write(struct super_block *sb, int level)
{
percpu_down_write(sb->s_writers.rw_sem + level-1);
/*
* We are going to return to userspace and forget about this lock, the
* ownership goes to the caller of thaw_super() which does unlock.
*
* FIXME: we should do this before return from freeze_super() after we
* called sync_filesystem(sb) and s_op->freeze_fs(sb), and thaw_super()
* should re-acquire these locks before s_op->unfreeze_fs(sb). However
* this leads to lockdep false-positives, so currently we do the early
* release right after acquire.
*/
percpu_rwsem_release(sb->s_writers.rw_sem + level-1, 0, _THIS_IP_);
}
static void sb_freeze_unlock(struct super_block *sb)
/*
* We are going to return to userspace and forget about these locks, the
* ownership goes to the caller of thaw_super() which does unlock().
*/
static void lockdep_sb_freeze_release(struct super_block *sb)
{
int level;
for (level = SB_FREEZE_LEVELS - 1; level >= 0; level--)
percpu_rwsem_release(sb->s_writers.rw_sem + level, 0, _THIS_IP_);
}
/*
* Tell lockdep we are holding these locks before we call ->unfreeze_fs(sb).
*/
static void lockdep_sb_freeze_acquire(struct super_block *sb)
{
int level;
for (level = 0; level < SB_FREEZE_LEVELS; ++level)
percpu_rwsem_acquire(sb->s_writers.rw_sem + level, 0, _THIS_IP_);
}
static void sb_freeze_unlock(struct super_block *sb)
{
int level;
for (level = SB_FREEZE_LEVELS - 1; level >= 0; level--)
percpu_up_write(sb->s_writers.rw_sem + level);
@ -1379,10 +1388,11 @@ int freeze_super(struct super_block *sb)
}
}
/*
* This is just for debugging purposes so that fs can warn if it
* sees write activity when frozen is set to SB_FREEZE_COMPLETE.
* For debugging purposes so that fs can warn if it sees write activity
* when frozen is set to SB_FREEZE_COMPLETE, and for thaw_super().
*/
sb->s_writers.frozen = SB_FREEZE_COMPLETE;
lockdep_sb_freeze_release(sb);
up_write(&sb->s_umount);
return 0;
}
@ -1399,7 +1409,7 @@ int thaw_super(struct super_block *sb)
int error;
down_write(&sb->s_umount);
if (sb->s_writers.frozen == SB_UNFROZEN) {
if (sb->s_writers.frozen != SB_FREEZE_COMPLETE) {
up_write(&sb->s_umount);
return -EINVAL;
}
@ -1409,11 +1419,14 @@ int thaw_super(struct super_block *sb)
goto out;
}
lockdep_sb_freeze_acquire(sb);
if (sb->s_op->unfreeze_fs) {
error = sb->s_op->unfreeze_fs(sb);
if (error) {
printk(KERN_ERR
"VFS:Filesystem thaw failed\n");
lockdep_sb_freeze_release(sb);
up_write(&sb->s_umount);
return error;
}

22
lib/iov_iter.c
View File

@ -1139,6 +1139,28 @@ const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags)
}
EXPORT_SYMBOL(dup_iter);
/**
* import_iovec() - Copy an array of &struct iovec from userspace
* into the kernel, check that it is valid, and initialize a new
* &struct iov_iter iterator to access it.
*
* @type: One of %READ or %WRITE.
* @uvector: Pointer to the userspace array.
* @nr_segs: Number of elements in userspace array.
* @fast_segs: Number of elements in @iov.
* @iov: (input and output parameter) Pointer to pointer to (usually small
* on-stack) kernel array.
* @i: Pointer to iterator that will be initialized on success.
*
* If the array pointed to by *@iov is large enough to hold all @nr_segs,
* then this function places %NULL in *@iov on return. Otherwise, a new
* array will be allocated and the result placed in *@iov. This means that
* the caller may call kfree() on *@iov regardless of whether the small
* on-stack array was used or not (and regardless of whether this function
* returns an error or not).
*
* Return: 0 on success or negative error code on error.
*/
int import_iovec(int type, const struct iovec __user * uvector,
unsigned nr_segs, unsigned fast_segs,
struct iovec **iov, struct iov_iter *i)