mainline inclusion from mainline-v6.15-rc1 commit 287906b20035a04a234d1a3c64f760a5678387be category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IC1OPD CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- During mount option processing and negotiation with the server, the original user-specified rsize/wsize values were being modified directly. This makes it impossible to recover these values after a connection reset, leading to potential degraded performance after reconnection. The other problem is that When negotiating read and write sizes, there are cases where the negotiated values might calculate to zero, especially during reconnection when server->max_read or server->max_write might be reset. In general, these values come from the negotiation response. According to MS-SMB2 specification, these values should be at least 65536 bytes. This patch improves IO parameter handling: 1. Adds vol_rsize and vol_wsize fields to store the original user-specified values separately from the negotiated values 2. Uses got_rsize/got_wsize flags to determine if values were user-specified rather than checking for non-zero values, which is more reliable 3. Adds a prevent_zero_iosize() helper function to ensure IO sizes are never negotiated down to zero, which could happen in edge cases like when server->max_read/write is zero The changes make the CIFS client more resilient to unusual server responses and reconnection scenarios, preventing potential failures when IO sizes are calculated to be zero. Signed-off-by: Wang Zhaolong <wangzhaolong1@huawei.com> Signed-off-by: Steve French <stfrench@microsoft.com> Signed-off-by: Wang Zhaolong <wangzhaolong1@huawei.com> --- fs/smb/client/fs_context.c | 2 ++ fs/smb/client/fs_context.h | 3 +++ fs/smb/client/smb1ops.c | 6 +++--- fs/smb/client/smb2ops.c | 27 +++++++++++++++++++-------- fs/smb/common/smb2pdu.h | 3 +++ 5 files changed, 30 insertions(+), 11 deletions(-) diff --git a/fs/smb/client/fs_context.c b/fs/smb/client/fs_context.c index b3fb1db26eb3..f5750fc6d721 100644 --- a/fs/smb/client/fs_context.c +++ b/fs/smb/client/fs_context.c @@ -1243,10 +1243,11 @@ static int smb3_fs_context_parse_param(struct fs_context *fc, ctx->rasize = result.uint_32; break; case Opt_rsize: ctx->rsize = result.uint_32; ctx->got_rsize = true; + ctx->vol_rsize = ctx->rsize; break; case Opt_wsize: ctx->wsize = result.uint_32; ctx->got_wsize = true; if (ctx->wsize % PAGE_SIZE != 0) { @@ -1258,10 +1259,11 @@ static int smb3_fs_context_parse_param(struct fs_context *fc, cifs_dbg(VFS, "wsize rounded down to %d to multiple of PAGE_SIZE %ld\n", ctx->wsize, PAGE_SIZE); } } + ctx->vol_wsize = ctx->wsize; break; case Opt_acregmax: if (result.uint_32 > CIFS_MAX_ACTIMEO / HZ) { cifs_errorf(fc, "acregmax too large\n"); goto cifs_parse_mount_err; diff --git a/fs/smb/client/fs_context.h b/fs/smb/client/fs_context.h index bbd2063ab838..d0a2043ea446 100644 --- a/fs/smb/client/fs_context.h +++ b/fs/smb/client/fs_context.h @@ -251,10 +251,13 @@ struct smb3_fs_context { bool rdma:1; bool multichannel:1; bool use_client_guid:1; /* reuse existing guid for multichannel */ u8 client_guid[SMB2_CLIENT_GUID_SIZE]; + /* User-specified original r/wsize value */ + unsigned int vol_rsize; + unsigned int vol_wsize; unsigned int bsize; unsigned int rasize; unsigned int rsize; unsigned int wsize; unsigned int min_offload; diff --git a/fs/smb/client/smb1ops.c b/fs/smb/client/smb1ops.c index bc1bac36c1b2..740f9e4b4374 100644 --- a/fs/smb/client/smb1ops.c +++ b/fs/smb/client/smb1ops.c @@ -442,12 +442,12 @@ cifs_negotiate_wsize(struct cifs_tcon *tcon, struct smb3_fs_context *ctx) __u64 unix_cap = le64_to_cpu(tcon->fsUnixInfo.Capability); struct TCP_Server_Info *server = tcon->ses->server; unsigned int wsize; /* start with specified wsize, or default */ - if (ctx->wsize) - wsize = ctx->wsize; + if (ctx->got_wsize) + wsize = ctx->vol_wsize; else if (tcon->unix_ext && (unix_cap & CIFS_UNIX_LARGE_WRITE_CAP)) wsize = CIFS_DEFAULT_IOSIZE; else wsize = CIFS_DEFAULT_NON_POSIX_WSIZE; @@ -495,11 +495,11 @@ cifs_negotiate_rsize(struct cifs_tcon *tcon, struct smb3_fs_context *ctx) else if (server->capabilities & CAP_LARGE_READ_X) defsize = CIFS_DEFAULT_NON_POSIX_RSIZE; else defsize = server->maxBuf - sizeof(READ_RSP); - rsize = ctx->rsize ? ctx->rsize : defsize; + rsize = ctx->got_rsize ? ctx->vol_rsize : defsize; /* * no CAP_LARGE_READ_X? Then MS-CIFS states that we must limit this to * the client's MaxBufferSize. */ diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c index b809a616728f..91dbf48de9d0 100644 --- a/fs/smb/client/smb2ops.c +++ b/fs/smb/client/smb2ops.c @@ -432,33 +432,44 @@ smb2_negotiate(const unsigned int xid, if (rc == -EAGAIN) rc = -EHOSTDOWN; return rc; } +static inline unsigned int +prevent_zero_iosize(unsigned int size, const char *type) +{ + if (size == 0) { + cifs_dbg(VFS, "SMB: Zero %ssize calculated, using minimum value %u\n", + type, CIFS_MIN_DEFAULT_IOSIZE); + return CIFS_MIN_DEFAULT_IOSIZE; + } + return size; +} + static unsigned int smb2_negotiate_wsize(struct cifs_tcon *tcon, struct smb3_fs_context *ctx) { struct TCP_Server_Info *server = tcon->ses->server; unsigned int wsize; /* start with specified wsize, or default */ - wsize = ctx->wsize ? ctx->wsize : CIFS_DEFAULT_IOSIZE; + wsize = ctx->got_wsize ? ctx->vol_wsize : CIFS_DEFAULT_IOSIZE; wsize = min_t(unsigned int, wsize, server->max_write); if (!(server->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU)) wsize = min_t(unsigned int, wsize, SMB2_MAX_BUFFER_SIZE); - return wsize; + return prevent_zero_iosize(wsize, "w"); } static unsigned int smb3_negotiate_wsize(struct cifs_tcon *tcon, struct smb3_fs_context *ctx) { struct TCP_Server_Info *server = tcon->ses->server; unsigned int wsize; /* start with specified wsize, or default */ - wsize = ctx->wsize ? ctx->wsize : SMB3_DEFAULT_IOSIZE; + wsize = ctx->got_wsize ? ctx->vol_wsize : SMB3_DEFAULT_IOSIZE; wsize = min_t(unsigned int, wsize, server->max_write); #ifdef CONFIG_CIFS_SMB_DIRECT if (server->rdma) { if (server->sign) /* @@ -476,37 +487,37 @@ smb3_negotiate_wsize(struct cifs_tcon *tcon, struct smb3_fs_context *ctx) } #endif if (!(server->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU)) wsize = min_t(unsigned int, wsize, SMB2_MAX_BUFFER_SIZE); - return wsize; + return prevent_zero_iosize(wsize, "w"); } static unsigned int smb2_negotiate_rsize(struct cifs_tcon *tcon, struct smb3_fs_context *ctx) { struct TCP_Server_Info *server = tcon->ses->server; unsigned int rsize; /* start with specified rsize, or default */ - rsize = ctx->rsize ? ctx->rsize : CIFS_DEFAULT_IOSIZE; + rsize = ctx->got_rsize ? ctx->vol_rsize : CIFS_DEFAULT_IOSIZE; rsize = min_t(unsigned int, rsize, server->max_read); if (!(server->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU)) rsize = min_t(unsigned int, rsize, SMB2_MAX_BUFFER_SIZE); - return rsize; + return prevent_zero_iosize(rsize, "r"); } static unsigned int smb3_negotiate_rsize(struct cifs_tcon *tcon, struct smb3_fs_context *ctx) { struct TCP_Server_Info *server = tcon->ses->server; unsigned int rsize; /* start with specified rsize, or default */ - rsize = ctx->rsize ? ctx->rsize : SMB3_DEFAULT_IOSIZE; + rsize = ctx->got_rsize ? ctx->vol_rsize : SMB3_DEFAULT_IOSIZE; rsize = min_t(unsigned int, rsize, server->max_read); #ifdef CONFIG_CIFS_SMB_DIRECT if (server->rdma) { if (server->sign) /* @@ -525,11 +536,11 @@ smb3_negotiate_rsize(struct cifs_tcon *tcon, struct smb3_fs_context *ctx) #endif if (!(server->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU)) rsize = min_t(unsigned int, rsize, SMB2_MAX_BUFFER_SIZE); - return rsize; + return prevent_zero_iosize(rsize, "r"); } /* * compare two interfaces a and b * return 0 if everything matches. diff --git a/fs/smb/common/smb2pdu.h b/fs/smb/common/smb2pdu.h index c3ee42188d25..1af827ae757e 100644 --- a/fs/smb/common/smb2pdu.h +++ b/fs/smb/common/smb2pdu.h @@ -93,10 +93,13 @@ * pages in a single call. With PAGE_SIZE == 4k, this means we can * fill a single wsize request with a single call. */ #define SMB3_DEFAULT_IOSIZE (4 * 1024 * 1024) +/* According to MS-SMB2 specification The minimum recommended value is 65536.*/ +#define CIFS_MIN_DEFAULT_IOSIZE (65536) + /* * SMB2 Header Definition * * "MBZ" : Must be Zero * "BB" : BugBug, Something to check/review/analyze later -- 2.34.3