The patch below does not apply to the 6.0-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
Possible dependencies:
f7f291e14dde ("cifs: fix oops during encryption") 76894f3e2f71 ("cifs: improve symlink handling for smb2+") a4e430c8c8ba ("cifs: replace kfree() with kfree_sensitive() for sensitive data")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From f7f291e14dde32a07b1f0aa06921d28f875a7b54 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara pc@cjr.nz Date: Sun, 11 Dec 2022 18:18:55 -0300 Subject: [PATCH] cifs: fix oops during encryption
When running xfstests against Azure the following oops occurred on an arm64 system
Unable to handle kernel write to read-only memory at virtual address ffff0001221cf000 Mem abort info: ESR = 0x9600004f EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x0f: level 3 permission fault Data abort info: ISV = 0, ISS = 0x0000004f CM = 0, WnR = 1 swapper pgtable: 4k pages, 48-bit VAs, pgdp=00000000294f3000 [ffff0001221cf000] pgd=18000001ffff8003, p4d=18000001ffff8003, pud=18000001ff82e003, pmd=18000001ff71d003, pte=00600001221cf787 Internal error: Oops: 9600004f [#1] PREEMPT SMP ... pstate: 80000005 (Nzcv daif -PAN -UAO -TCO BTYPE=--) pc : __memcpy+0x40/0x230 lr : scatterwalk_copychunks+0xe0/0x200 sp : ffff800014e92de0 x29: ffff800014e92de0 x28: ffff000114f9de80 x27: 0000000000000008 x26: 0000000000000008 x25: ffff800014e92e78 x24: 0000000000000008 x23: 0000000000000001 x22: 0000040000000000 x21: ffff000000000000 x20: 0000000000000001 x19: ffff0001037c4488 x18: 0000000000000014 x17: 235e1c0d6efa9661 x16: a435f9576b6edd6c x15: 0000000000000058 x14: 0000000000000001 x13: 0000000000000008 x12: ffff000114f2e590 x11: ffffffffffffffff x10: 0000040000000000 x9 : ffff8000105c3580 x8 : 2e9413b10000001a x7 : 534b4410fb86b005 x6 : 534b4410fb86b005 x5 : ffff0001221cf008 x4 : ffff0001037c4490 x3 : 0000000000000001 x2 : 0000000000000008 x1 : ffff0001037c4488 x0 : ffff0001221cf000 Call trace: __memcpy+0x40/0x230 scatterwalk_map_and_copy+0x98/0x100 crypto_ccm_encrypt+0x150/0x180 crypto_aead_encrypt+0x2c/0x40 crypt_message+0x750/0x880 smb3_init_transform_rq+0x298/0x340 smb_send_rqst.part.11+0xd8/0x180 smb_send_rqst+0x3c/0x100 compound_send_recv+0x534/0xbc0 smb2_query_info_compound+0x32c/0x440 smb2_set_ea+0x438/0x4c0 cifs_xattr_set+0x5d4/0x7c0
This is because in scatterwalk_copychunks(), we attempted to write to a buffer (@sign) that was allocated in the stack (vmalloc area) by crypt_message() and thus accessing its remaining 8 (x2) bytes ended up crossing a page boundary.
To simply fix it, we could just pass @sign kmalloc'd from crypt_message() and then we're done. Luckily, we don't seem to pass any other vmalloc'd buffers in smb_rqst::rq_iov...
Instead, let's map the correct pages and offsets from vmalloc buffers as well in cifs_sg_set_buf() and then avoiding such oopses.
Signed-off-by: Paulo Alcantara (SUSE) pc@cjr.nz Cc: stable@vger.kernel.org Signed-off-by: Steve French stfrench@microsoft.com
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h index cd3a173e65b1..703685e2db5e 100644 --- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -13,6 +13,8 @@ #include <linux/in6.h> #include <linux/inet.h> #include <linux/slab.h> +#include <linux/scatterlist.h> +#include <linux/mm.h> #include <linux/mempool.h> #include <linux/workqueue.h> #include <linux/utsname.h> @@ -2140,4 +2142,70 @@ static inline void move_cifs_info_to_smb2(struct smb2_file_all_info *dst, const dst->FileNameLength = src->FileNameLength; }
+static inline unsigned int cifs_get_num_sgs(const struct smb_rqst *rqst, + int num_rqst, + const u8 *sig) +{ + unsigned int len, skip; + unsigned int nents = 0; + unsigned long addr; + int i, j; + + /* Assumes the first rqst has a transform header as the first iov. + * I.e. + * rqst[0].rq_iov[0] is transform header + * rqst[0].rq_iov[1+] data to be encrypted/decrypted + * rqst[1+].rq_iov[0+] data to be encrypted/decrypted + */ + for (i = 0; i < num_rqst; i++) { + /* + * The first rqst has a transform header where the + * first 20 bytes are not part of the encrypted blob. + */ + for (j = 0; j < rqst[i].rq_nvec; j++) { + struct kvec *iov = &rqst[i].rq_iov[j]; + + skip = (i == 0) && (j == 0) ? 20 : 0; + addr = (unsigned long)iov->iov_base + skip; + if (unlikely(is_vmalloc_addr((void *)addr))) { + len = iov->iov_len - skip; + nents += DIV_ROUND_UP(offset_in_page(addr) + len, + PAGE_SIZE); + } else { + nents++; + } + } + nents += rqst[i].rq_npages; + } + nents += DIV_ROUND_UP(offset_in_page(sig) + SMB2_SIGNATURE_SIZE, PAGE_SIZE); + return nents; +} + +/* We can not use the normal sg_set_buf() as we will sometimes pass a + * stack object as buf. + */ +static inline struct scatterlist *cifs_sg_set_buf(struct scatterlist *sg, + const void *buf, + unsigned int buflen) +{ + unsigned long addr = (unsigned long)buf; + unsigned int off = offset_in_page(addr); + + addr &= PAGE_MASK; + if (unlikely(is_vmalloc_addr((void *)addr))) { + do { + unsigned int len = min_t(unsigned int, buflen, PAGE_SIZE - off); + + sg_set_page(sg++, vmalloc_to_page((void *)addr), len, off); + + off = 0; + addr += PAGE_SIZE; + buflen -= len; + } while (buflen); + } else { + sg_set_page(sg++, virt_to_page(addr), buflen, off); + } + return sg; +} + #endif /* _CIFS_GLOB_H */ diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h index f216fa269c85..9c6147ca029d 100644 --- a/fs/cifs/cifsproto.h +++ b/fs/cifs/cifsproto.h @@ -600,8 +600,8 @@ int setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw); int cifs_alloc_hash(const char *name, struct shash_desc **sdesc); void cifs_free_hash(struct shash_desc **sdesc);
-extern void rqst_page_get_length(struct smb_rqst *rqst, unsigned int page, - unsigned int *len, unsigned int *offset); +void rqst_page_get_length(const struct smb_rqst *rqst, unsigned int page, + unsigned int *len, unsigned int *offset); struct cifs_chan * cifs_ses_find_chan(struct cifs_ses *ses, struct TCP_Server_Info *server); int cifs_try_adding_channels(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses); diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c index 3e68d8208cf5..1cbecd64d697 100644 --- a/fs/cifs/misc.c +++ b/fs/cifs/misc.c @@ -1136,8 +1136,8 @@ cifs_free_hash(struct shash_desc **sdesc) * @len: Where to store the length for this page: * @offset: Where to store the offset for this page */ -void rqst_page_get_length(struct smb_rqst *rqst, unsigned int page, - unsigned int *len, unsigned int *offset) +void rqst_page_get_length(const struct smb_rqst *rqst, unsigned int page, + unsigned int *len, unsigned int *offset) { *len = rqst->rq_pagesz; *offset = (page == 0) ? rqst->rq_offset : 0; diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index 72b22d033ed5..6e772b31e02a 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -4204,69 +4204,82 @@ fill_transform_hdr(struct smb2_transform_hdr *tr_hdr, unsigned int orig_len, memcpy(&tr_hdr->SessionId, &shdr->SessionId, 8); }
-/* We can not use the normal sg_set_buf() as we will sometimes pass a - * stack object as buf. - */ -static inline void smb2_sg_set_buf(struct scatterlist *sg, const void *buf, - unsigned int buflen) +static void *smb2_aead_req_alloc(struct crypto_aead *tfm, const struct smb_rqst *rqst, + int num_rqst, const u8 *sig, u8 **iv, + struct aead_request **req, struct scatterlist **sgl, + unsigned int *num_sgs) { - void *addr; - /* - * VMAP_STACK (at least) puts stack into the vmalloc address space - */ - if (is_vmalloc_addr(buf)) - addr = vmalloc_to_page(buf); - else - addr = virt_to_page(buf); - sg_set_page(sg, addr, buflen, offset_in_page(buf)); + unsigned int req_size = sizeof(**req) + crypto_aead_reqsize(tfm); + unsigned int iv_size = crypto_aead_ivsize(tfm); + unsigned int len; + u8 *p; + + *num_sgs = cifs_get_num_sgs(rqst, num_rqst, sig); + + len = iv_size; + len += crypto_aead_alignmask(tfm) & ~(crypto_tfm_ctx_alignment() - 1); + len = ALIGN(len, crypto_tfm_ctx_alignment()); + len += req_size; + len = ALIGN(len, __alignof__(struct scatterlist)); + len += *num_sgs * sizeof(**sgl); + + p = kmalloc(len, GFP_ATOMIC); + if (!p) + return NULL; + + *iv = (u8 *)PTR_ALIGN(p, crypto_aead_alignmask(tfm) + 1); + *req = (struct aead_request *)PTR_ALIGN(*iv + iv_size, + crypto_tfm_ctx_alignment()); + *sgl = (struct scatterlist *)PTR_ALIGN((u8 *)*req + req_size, + __alignof__(struct scatterlist)); + return p; }
-/* Assumes the first rqst has a transform header as the first iov. - * I.e. - * rqst[0].rq_iov[0] is transform header - * rqst[0].rq_iov[1+] data to be encrypted/decrypted - * rqst[1+].rq_iov[0+] data to be encrypted/decrypted - */ -static struct scatterlist * -init_sg(int num_rqst, struct smb_rqst *rqst, u8 *sign) +static void *smb2_get_aead_req(struct crypto_aead *tfm, const struct smb_rqst *rqst, + int num_rqst, const u8 *sig, u8 **iv, + struct aead_request **req, struct scatterlist **sgl) { - unsigned int sg_len; + unsigned int off, len, skip; struct scatterlist *sg; - unsigned int i; - unsigned int j; - unsigned int idx = 0; - int skip; - - sg_len = 1; - for (i = 0; i < num_rqst; i++) - sg_len += rqst[i].rq_nvec + rqst[i].rq_npages; + unsigned int num_sgs; + unsigned long addr; + int i, j; + void *p;
- sg = kmalloc_array(sg_len, sizeof(struct scatterlist), GFP_KERNEL); - if (!sg) + p = smb2_aead_req_alloc(tfm, rqst, num_rqst, sig, iv, req, sgl, &num_sgs); + if (!p) return NULL;
- sg_init_table(sg, sg_len); + sg_init_table(*sgl, num_sgs); + sg = *sgl; + + /* Assumes the first rqst has a transform header as the first iov. + * I.e. + * rqst[0].rq_iov[0] is transform header + * rqst[0].rq_iov[1+] data to be encrypted/decrypted + * rqst[1+].rq_iov[0+] data to be encrypted/decrypted + */ for (i = 0; i < num_rqst; i++) { + /* + * The first rqst has a transform header where the + * first 20 bytes are not part of the encrypted blob. + */ for (j = 0; j < rqst[i].rq_nvec; j++) { - /* - * The first rqst has a transform header where the - * first 20 bytes are not part of the encrypted blob - */ - skip = (i == 0) && (j == 0) ? 20 : 0; - smb2_sg_set_buf(&sg[idx++], - rqst[i].rq_iov[j].iov_base + skip, - rqst[i].rq_iov[j].iov_len - skip); - } + struct kvec *iov = &rqst[i].rq_iov[j];
+ skip = (i == 0) && (j == 0) ? 20 : 0; + addr = (unsigned long)iov->iov_base + skip; + len = iov->iov_len - skip; + sg = cifs_sg_set_buf(sg, (void *)addr, len); + } for (j = 0; j < rqst[i].rq_npages; j++) { - unsigned int len, offset; - - rqst_page_get_length(&rqst[i], j, &len, &offset); - sg_set_page(&sg[idx++], rqst[i].rq_pages[j], len, offset); + rqst_page_get_length(&rqst[i], j, &len, &off); + sg_set_page(sg++, rqst[i].rq_pages[j], len, off); } } - smb2_sg_set_buf(&sg[idx], sign, SMB2_SIGNATURE_SIZE); - return sg; + cifs_sg_set_buf(sg, sig, SMB2_SIGNATURE_SIZE); + + return p; }
static int @@ -4314,11 +4327,11 @@ crypt_message(struct TCP_Server_Info *server, int num_rqst, u8 sign[SMB2_SIGNATURE_SIZE] = {}; u8 key[SMB3_ENC_DEC_KEY_SIZE]; struct aead_request *req; - char *iv; - unsigned int iv_len; + u8 *iv; DECLARE_CRYPTO_WAIT(wait); struct crypto_aead *tfm; unsigned int crypt_len = le32_to_cpu(tr_hdr->OriginalMessageSize); + void *creq;
rc = smb2_get_enc_key(server, le64_to_cpu(tr_hdr->SessionId), enc, key); if (rc) { @@ -4352,32 +4365,15 @@ crypt_message(struct TCP_Server_Info *server, int num_rqst, return rc; }
- req = aead_request_alloc(tfm, GFP_KERNEL); - if (!req) { - cifs_server_dbg(VFS, "%s: Failed to alloc aead request\n", __func__); + creq = smb2_get_aead_req(tfm, rqst, num_rqst, sign, &iv, &req, &sg); + if (unlikely(!creq)) return -ENOMEM; - }
if (!enc) { memcpy(sign, &tr_hdr->Signature, SMB2_SIGNATURE_SIZE); crypt_len += SMB2_SIGNATURE_SIZE; }
- sg = init_sg(num_rqst, rqst, sign); - if (!sg) { - cifs_server_dbg(VFS, "%s: Failed to init sg\n", __func__); - rc = -ENOMEM; - goto free_req; - } - - iv_len = crypto_aead_ivsize(tfm); - iv = kzalloc(iv_len, GFP_KERNEL); - if (!iv) { - cifs_server_dbg(VFS, "%s: Failed to alloc iv\n", __func__); - rc = -ENOMEM; - goto free_sg; - } - if ((server->cipher_type == SMB2_ENCRYPTION_AES128_GCM) || (server->cipher_type == SMB2_ENCRYPTION_AES256_GCM)) memcpy(iv, (char *)tr_hdr->Nonce, SMB3_AES_GCM_NONCE); @@ -4386,6 +4382,7 @@ crypt_message(struct TCP_Server_Info *server, int num_rqst, memcpy(iv + 1, (char *)tr_hdr->Nonce, SMB3_AES_CCM_NONCE); }
+ aead_request_set_tfm(req, tfm); aead_request_set_crypt(req, sg, sg, crypt_len, iv); aead_request_set_ad(req, assoc_data_len);
@@ -4398,11 +4395,7 @@ crypt_message(struct TCP_Server_Info *server, int num_rqst, if (!rc && enc) memcpy(&tr_hdr->Signature, sign, SMB2_SIGNATURE_SIZE);
- kfree_sensitive(iv); -free_sg: - kfree_sensitive(sg); -free_req: - kfree_sensitive(req); + kfree_sensitive(creq); return rc; }