litmus-rt.git - The LITMUS^RT kernel.

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author	Dave Chinner <dchinner@redhat.com>	2010-06-23 21:15:33 -0400
committer	Dave Chinner <david@fromorbit.com>	2010-06-23 21:15:33 -0400
commit	7124fe0a5b619d65b739477b3b55a20bf805b06d (patch)
tree	be333ebdcc7df735070dbc1441c1d59682d06132 /include/linux/stackprotector.h
parent	7dce11dbac54fce777eea0f5fb25b2694ccd7900 (diff)

xfs: validate untrusted inode numbers during lookup

When we decode a handle or do a bulkstat lookup, we are using an inode number we cannot trust to be valid. If we are deleting inode chunks from disk (default noikeep mode), then we cannot trust the on disk inode buffer for any given inode number to correctly reflect whether the inode has been unlinked as the di_mode nor the generation number may have been updated on disk. This is due to the fact that when we delete an inode chunk, we do not write the clusters back to disk when they are removed - instead we mark them stale to avoid them being written back potentially over the top of something that has been subsequently allocated at that location. The result is that we can have locations of disk that look like they contain valid inodes but in reality do not. Hence we cannot simply convert the inode number to a block number and read the location from disk to determine if the inode is valid or not. As a result, and XFS_IGET_BULKSTAT lookup needs to actually look the inode up in the inode allocation btree to determine if the inode number is valid or not. It should be noted even on ikeep filesystems, there is the possibility that blocks on disk may look like valid inode clusters. e.g. if there are filesystem images hosted on the filesystem. Hence even for ikeep filesystems we really need to validate that the inode number is valid before issuing the inode buffer read. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>

Diffstat (limited to 'include/linux/stackprotector.h')

0 files changed, 0 insertions, 0 deletions

/* * CTR: Counter mode * * (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com> * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the Free * Software Foundation; either version 2 of the License, or (at your option) * any later version. * */ #include <crypto/algapi.h> #include <crypto/ctr.h> #include <crypto/internal/skcipher.h> #include <linux/err.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/random.h> #include <linux/scatterlist.h> #include <linux/slab.h> struct crypto_ctr_ctx { struct crypto_cipher *child; }; struct crypto_rfc3686_ctx { struct crypto_ablkcipher *child; u8 nonce[CTR_RFC3686_NONCE_SIZE]; }; struct crypto_rfc3686_req_ctx { u8 iv[CTR_RFC3686_BLOCK_SIZE]; struct ablkcipher_request subreq CRYPTO_MINALIGN_ATTR; }; static int crypto_ctr_setkey(struct crypto_tfm *parent, const u8 *key, unsigned int keylen) { struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(parent); struct crypto_cipher *child = ctx->child; int err; crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK); crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) & CRYPTO_TFM_REQ_MASK); err = crypto_cipher_setkey(child, key, keylen); crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) & CRYPTO_TFM_RES_MASK); return err; } static void crypto_ctr_crypt_final(struct blkcipher_walk *walk, struct crypto_cipher *tfm) { unsigned int bsize = crypto_cipher_blocksize(tfm); unsigned long alignmask = crypto_cipher_alignmask(tfm); u8 *ctrblk = walk->iv; u8 tmp[bsize + alignmask]; u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1); u8 *src = walk->src.virt.addr; u8 *dst = walk->dst.virt.addr; unsigned int nbytes = walk->nbytes; crypto_cipher_encrypt_one(tfm, keystream, ctrblk); crypto_xor(keystream, src, nbytes); memcpy(dst, keystream, nbytes); crypto_inc(ctrblk, bsize); } static int crypto_ctr_crypt_segment(struct blkcipher_walk *walk, struct crypto_cipher *tfm) { void (*fn)(struct crypto_tfm *, u8 *, const u8 *) = crypto_cipher_alg(tfm)->cia_encrypt; unsigned int bsize = crypto_cipher_blocksize(tfm); u8 *ctrblk = walk->iv; u8 *src = walk->src.virt.addr; u8 *dst = walk->dst.virt.addr; unsigned int nbytes = walk->nbytes; do { /* create keystream */ fn(crypto_cipher_tfm(tfm), dst, ctrblk); crypto_xor(dst, src, bsize); /* increment counter in counterblock */ crypto_inc(ctrblk, bsize); src += bsize; dst += bsize; } while ((nbytes -= bsize) >= bsize); return nbytes; } static int crypto_ctr_crypt_inplace(struct blkcipher_walk *walk, struct crypto_cipher *tfm) { void (*fn)(struct crypto_tfm *, u8 *, const u8 *) = crypto_cipher_alg(tfm)->cia_encrypt; unsigned int bsize = crypto_cipher_blocksize(tfm); unsigned long alignmask = crypto_cipher_alignmask(tfm); unsigned int nbytes = walk->nbytes; u8 *ctrblk = walk->iv; u8 *src = walk->src.virt.addr; u8 tmp[bsize + alignmask]; u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1); do { /* create keystream */ fn(crypto_cipher_tfm(tfm), keystream, ctrblk); crypto_xor(src, keystream, bsize); /* increment counter in counterblock */ crypto_inc(ctrblk, bsize); src += bsize; } while ((nbytes -= bsize) >= bsize); return nbytes; } static int crypto_ctr_crypt(struct blkcipher_desc *desc, struct scatterlist *dst, struct scatterlist *src, unsigned int nbytes) { struct blkcipher_walk walk; struct crypto_blkcipher *tfm = desc->tfm; struct crypto_ctr_ctx *ctx = crypto_blkcipher_ctx(tfm); struct crypto_cipher *child = ctx->child; unsigned int bsize = crypto_cipher_blocksize(child); int err; blkcipher_walk_init(&walk, dst, src, nbytes); err = blkcipher_walk_virt_block(desc, &walk, bsize); while (walk.nbytes >= bsize) { if (walk.src.virt.addr == walk.dst.virt.addr) nbytes = crypto_ctr_crypt_inplace(&walk, child); else nbytes = crypto_ctr_crypt_segment(&walk, child); err = blkcipher_walk_done(desc, &walk, nbytes); } if (walk.nbytes) { crypto_ctr_crypt_final(&walk, child); err = blkcipher_walk_done(desc, &walk, 0); } return err; } static int crypto_ctr_init_tfm(struct crypto_tfm *tfm) { struct crypto_instance *inst = (void *)tfm->__crt_alg; struct crypto_spawn *spawn = crypto_instance_ctx(inst); struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm); struct crypto_cipher *cipher; cipher = crypto_spawn_cipher(spawn); if (IS_ERR(cipher)) return PTR_ERR(cipher); ctx->child = cipher; return 0; } static void crypto_ctr_exit_tfm(struct crypto_tfm *tfm) { struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm); crypto_free_cipher(ctx->child); } static struct crypto_instance *crypto_ctr_alloc(struct rtattr **tb) { struct crypto_instance *inst; struct crypto_alg *alg; int err; err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER); if (err) return ERR_PTR(err); alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER, CRYPTO_ALG_TYPE_MASK); if (IS_ERR(alg)) return ERR_CAST(alg); /* Block size must be >= 4 bytes. */ err = -EINVAL; if (alg->cra_blocksize < 4) goto out_put_alg; /* If this is false we'd fail the alignment of crypto_inc. */ if (alg->cra_blocksize % 4) goto out_put_alg; inst = crypto_alloc_instance("ctr", alg); if (IS_ERR(inst)) goto out; inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER; inst->alg.cra_priority = alg->cra_priority; inst->alg.cra_blocksize = 1; inst->alg.cra_alignmask = alg->cra_alignmask | (__alignof__(u32) - 1); inst->alg.cra_type = &crypto_blkcipher_type; inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize; inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize; inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize; inst->alg.cra_ctxsize = sizeof(struct crypto_ctr_ctx); inst->alg.cra_init = crypto_ctr_init_tfm; inst->alg.cra_exit = crypto_ctr_exit_tfm; inst->alg.cra_blkcipher.setkey = crypto_ctr_setkey;


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