Memory safety (use-after-free, double-free)

HIGH
torvalds/linux
Commit: 048091722259
Affected: v7.0-rc6 and earlier (baseline for this patch, before this v7.1-rc-part1 ksmbd-srv-fixes merge)
2026-04-16 06:32 UTC

Description

The commit bundles fixes for memory-safety vulnerabilities in the ksmbd SMB server (smbdirect path and related code). The primary issues addressed are memory-corruption risks such as use-after-free and double-free in the SMB Direct path (e.g., handling and ownership of request objects in smbdirect_send paths, and the flow where a request is moved to a batch and should not be freed), as well as a use-after-free in the close path for durable/async operations. Additional changes address a potential crypto-message use-after-free, a memory leak in session setup, validation improvements (EA name length), and safer handling of related FSCC structures to reduce the risk of out-of-bounds or invalid memory access. Overall, these changes are aimed at mitigating memory-safety defects that could lead to crashes or code execution, rather than pure functionality changes.

Commit Details

Author: Linus Torvalds

Date: 2026-04-16 02:14 UTC

Message:

Merge tag 'v7.1-rc-part1-ksmbd-srv-fixes' of git://git.samba.org/ksmbd Pull smb server updates from Steve French: - smbdirect double free fixes - Add some smbdirect logging - Minor cleanup in crypto, and smbdirect and in IPC handling - Minor cleanup to move header info to common FSCC code - Fix crypt message use after free - Fix memory leak in session setup - Fix for DACL parsing - Fix EA name length validation - Reconnect fix - Fix use after free in close * tag 'v7.1-rc-part1-ksmbd-srv-fixes' of git://git.samba.org/ksmbd: smb: smbdirect: add some logging to SMBDIRECT_CHECK_STATUS_{WARN,DISCONNECT}() smb: smbdirect: introduce smbdirect_socket.logging infrastructure smb: smbdirect: let smbdirect.h include #include <linux/types.h> smb: server: avoid double-free in smb_direct_free_sendmsg after smb_direct_flush_send_list() smb: client: avoid double-free in smbd_free_send_io() after smbd_send_batch_flush() ksmbd: fix use-after-free from async crypto on Qualcomm crypto engine ksmbd: fix mechToken leak when SPNEGO decode fails after token alloc ksmbd: require 3 sub-authorities before reading sub_auth[2] ksmbd: validate EaNameLength in smb2_get_ea() ksmbd: Remove unnecessary selection of CRYPTO_ECB ksmbd: validate owner of durable handle on reconnect ksmbd: fix use-after-free in __ksmbd_close_fd() via durable scavenger ksmbd: ipc: use kzalloc_flex and __counted_by smb: move filesystem_vol_info into common/fscc.h smb: move file_basic_info into common/fscc.h smb: move some definitions from common/smb2pdu.h into common/fscc.h

Triage Assessment

Vulnerability Type: Memory safety (use-after-free, double-free)

Confidence: HIGH

Reasoning:

Commit message and code changes indicate fixes for memory safety issues (double free and use-after-free) in smbdirect and related crypto handling, along with related validation fixes (EA name length, reconnect owner). These are classic memory corruption/security fixes (RCE via use-after-free/double-free, information disclosure via leaks mitigated).

Verification Assessment

Vulnerability Type: Memory safety (use-after-free, double-free)

Confidence: HIGH

Affected Versions: v7.0-rc6 and earlier (baseline for this patch, before this v7.1-rc-part1 ksmbd-srv-fixes merge)

Code Diff

diff --git a/fs/smb/client/smb1pdu.h b/fs/smb/client/smb1pdu.h index 97f7e1244a8b3b..7584e94d9b2bfa 100644 --- a/fs/smb/client/smb1pdu.h +++ b/fs/smb/client/smb1pdu.h @@ -2061,15 +2061,6 @@ typedef struct { __le32 EASize; } __packed FILE_INFO_STANDARD; /* level 1 SetPath/FileInfo */ -typedef struct { - __le64 CreationTime; - __le64 LastAccessTime; - __le64 LastWriteTime; - __le64 ChangeTime; - __le32 Attributes; - __u32 Pad; -} __packed FILE_BASIC_INFO; /* size info, level 0x101 */ - struct file_allocation_info { __le64 AllocationSize; /* Note old Samba srvr rounds this up too much */ } __packed; /* size used on disk, for level 0x103 for set, 0x105 for query */ diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c index 5188218c25be42..59d7418cc48063 100644 --- a/fs/smb/client/smb2pdu.c +++ b/fs/smb/client/smb2pdu.c @@ -6147,8 +6147,8 @@ SMB2_QFS_attr(const unsigned int xid, struct cifs_tcon *tcon, max_len = sizeof(struct smb3_fs_ss_info); min_len = sizeof(struct smb3_fs_ss_info); } else if (level == FS_VOLUME_INFORMATION) { - max_len = sizeof(struct smb3_fs_vol_info) + MAX_VOL_LABEL_LEN; - min_len = sizeof(struct smb3_fs_vol_info); + max_len = sizeof(struct filesystem_vol_info) + MAX_VOL_LABEL_LEN; + min_len = sizeof(struct filesystem_vol_info); } else { cifs_dbg(FYI, "Invalid qfsinfo level %d\n", level); return -EINVAL; @@ -6203,9 +6203,9 @@ SMB2_QFS_attr(const unsigned int xid, struct cifs_tcon *tcon, tcon->perf_sector_size = le32_to_cpu(ss_info->PhysicalBytesPerSectorForPerf); } else if (level == FS_VOLUME_INFORMATION) { - struct smb3_fs_vol_info *vol_info = (struct smb3_fs_vol_info *) + struct filesystem_vol_info *vol_info = (struct filesystem_vol_info *) (offset + (char *)rsp); - tcon->vol_serial_number = vol_info->VolumeSerialNumber; + tcon->vol_serial_number = le32_to_cpu(vol_info->VolumeSerialNumber); tcon->vol_create_time = vol_info->VolumeCreationTime; } diff --git a/fs/smb/client/smbdirect.c b/fs/smb/client/smbdirect.c index c79304012b08c3..46165810501331 100644 --- a/fs/smb/client/smbdirect.c +++ b/fs/smb/client/smbdirect.c @@ -1551,17 +1551,25 @@ static int smbd_post_send_iter(struct smbdirect_socket *sc, rc = smbd_post_send(sc, batch, request); if (!rc) { + /* + * From here request is moved to batch + * and we should not free it explicitly. + */ + if (batch != &_batch) return 0; rc = smbd_send_batch_flush(sc, batch, true); if (!rc) return 0; + + goto err_flush; } err_dma: smbd_free_send_io(request); +err_flush: err_alloc: atomic_inc(&sc->send_io.credits.count); wake_up(&sc->send_io.credits.wait_queue); diff --git a/fs/smb/common/fscc.h b/fs/smb/common/fscc.h index 0123f34db1e891..b4ccddca925656 100644 --- a/fs/smb/common/fscc.h +++ b/fs/smb/common/fscc.h @@ -12,6 +12,220 @@ #ifndef _COMMON_SMB_FSCC_H #define _COMMON_SMB_FSCC_H +/* Reparse structures - see MS-FSCC 2.1.2 */ + +/* struct fsctl_reparse_info_req is empty, only response structs (see below) */ +struct reparse_data_buffer { + __le32 ReparseTag; + __le16 ReparseDataLength; + __u16 Reserved; + __u8 DataBuffer[]; /* Variable Length */ +} __packed; + +struct reparse_guid_data_buffer { + __le32 ReparseTag; + __le16 ReparseDataLength; + __u16 Reserved; + __u8 ReparseGuid[16]; + __u8 DataBuffer[]; /* Variable Length */ +} __packed; + +struct reparse_mount_point_data_buffer { + __le32 ReparseTag; + __le16 ReparseDataLength; + __u16 Reserved; + __le16 SubstituteNameOffset; + __le16 SubstituteNameLength; + __le16 PrintNameOffset; + __le16 PrintNameLength; + __u8 PathBuffer[]; /* Variable Length */ +} __packed; + +#define SYMLINK_FLAG_RELATIVE 0x00000001 + +struct reparse_symlink_data_buffer { + __le32 ReparseTag; + __le16 ReparseDataLength; + __u16 Reserved; + __le16 SubstituteNameOffset; + __le16 SubstituteNameLength; + __le16 PrintNameOffset; + __le16 PrintNameLength; + __le32 Flags; + __u8 PathBuffer[]; /* Variable Length */ +} __packed; + +/* For IO_REPARSE_TAG_NFS - see MS-FSCC 2.1.2.6 */ +#define NFS_SPECFILE_LNK 0x00000000014B4E4C +#define NFS_SPECFILE_CHR 0x0000000000524843 +#define NFS_SPECFILE_BLK 0x00000000004B4C42 +#define NFS_SPECFILE_FIFO 0x000000004F464946 +#define NFS_SPECFILE_SOCK 0x000000004B434F53 +struct reparse_nfs_data_buffer { + __le32 ReparseTag; + __le16 ReparseDataLength; + __u16 Reserved; + __le64 InodeType; /* NFS_SPECFILE_* */ + __u8 DataBuffer[]; +} __packed; + +/* For IO_REPARSE_TAG_LX_SYMLINK - see MS-FSCC 2.1.2.7 */ +struct reparse_wsl_symlink_data_buffer { + __le32 ReparseTag; + __le16 ReparseDataLength; + __u16 Reserved; + __le32 Version; /* Always 2 */ + __u8 Target[]; /* Variable Length UTF-8 string without nul-term */ +} __packed; + +/* See MS-FSCC 2.3.7 */ +struct duplicate_extents_to_file { + __u64 PersistentFileHandle; /* source file handle, opaque endianness */ + __u64 VolatileFileHandle; + __le64 SourceFileOffset; + __le64 TargetFileOffset; + __le64 ByteCount; /* Bytes to be copied */ +} __packed; + +/* See MS-FSCC 2.3.9 */ +#define DUPLICATE_EXTENTS_DATA_EX_SOURCE_ATOMIC 0x00000001 +struct duplicate_extents_to_file_ex { + __le64 StructureSize; /* MUST be set to 0x30 */ + __u64 PersistentFileHandle; /* source file handle, opaque endianness */ + __u64 VolatileFileHandle; + __le64 SourceFileOffset; + __le64 TargetFileOffset; + __le64 ByteCount; /* Bytes to be copied */ + __le32 Flags; + __le32 Reserved; +} __packed; + +/* See MS-FSCC 2.3.20 */ +struct fsctl_get_integrity_information_rsp { + __le16 ChecksumAlgorithm; + __le16 Reserved; + __le32 Flags; + __le32 ChecksumChunkSizeInBytes; + __le32 ClusterSizeInBytes; +} __packed; + +/* See MS-FSCC 2.3.52 */ +struct file_allocated_range_buffer { + __le64 file_offset; + __le64 length; +} __packed; + +/* See MS-FSCC 2.3.55 */ +struct fsctl_query_file_regions_req { + __le64 FileOffset; + __le64 Length; + __le32 DesiredUsage; + __le32 Reserved; +} __packed; + +/* DesiredUsage flags see MS-FSCC 2.3.56.1 */ +#define FILE_USAGE_INVALID_RANGE 0x00000000 +#define FILE_USAGE_VALID_CACHED_DATA 0x00000001 +#define FILE_USAGE_NONCACHED_DATA 0x00000002 +struct file_region_info { + __le64 FileOffset; + __le64 Length; + __le32 DesiredUsage; + __le32 Reserved; +} __packed; + +/* See MS-FSCC 2.3.56 */ +struct fsctl_query_file_region_rsp { + __le32 Flags; + __le32 TotalRegionEntryCount; + __le32 RegionEntryCount; + __u32 Reserved; + struct file_region_info Regions[]; +} __packed; + +/* See MS-FSCC 2.3.58 */ +struct fsctl_query_on_disk_vol_info_rsp { + __le64 DirectoryCount; + __le64 FileCount; + __le16 FsFormatMajVersion; + __le16 FsFormatMinVersion; + __u8 FsFormatName[24]; + __le64 FormatTime; + __le64 LastUpdateTime; + __u8 CopyrightInfo[68]; + __u8 AbstractInfo[68]; + __u8 FormatImplInfo[68]; + __u8 LastModifyImplInfo[68]; +} __packed; + +/* See MS-FSCC 2.3.73 */ +struct fsctl_set_integrity_information_req { + __le16 ChecksumAlgorithm; + __le16 Reserved; + __le32 Flags; +} __packed; + +/* See MS-FSCC 2.3.75 */ +struct fsctl_set_integrity_info_ex_req { + __u8 EnableIntegrity; + __u8 KeepState; + __u16 Reserved; + __le32 Flags; + __u8 Version; + __u8 Reserved2[7]; +} __packed; + +/* + * this goes in the ioctl buffer when doing FSCTL_SET_ZERO_DATA + * See MS-FSCC 2.3.85 + */ +struct file_zero_data_information { + __le64 FileOffset; + __le64 BeyondFinalZero; +} __packed; + +/* + * This level 18, although with struct with same name is different from cifs + * level 0x107. Level 0x107 has an extra u64 between AccessFlags and + * CurrentByteOffset. + * See MS-FSCC 2.4.2 + */ +struct smb2_file_all_info { /* data block encoding of response to level 18 */ + __le64 CreationTime; /* Beginning of FILE_BASIC_INFO equivalent */ + __le64 LastAccessTime; + __le64 LastWriteTime; + __le64 ChangeTime; + __le32 Attributes; + __u32 Pad1; /* End of FILE_BASIC_INFO_INFO equivalent */ + __le64 AllocationSize; /* Beginning of FILE_STANDARD_INFO equivalent */ + __le64 EndOfFile; /* size ie offset to first free byte in file */ + __le32 NumberOfLinks; /* hard links */ + __u8 DeletePending; + __u8 Directory; + __u16 Pad2; /* End of FILE_STANDARD_INFO equivalent */ + __le64 IndexNumber; + __le32 EASize; + __le32 AccessFlags; + __le64 CurrentByteOffset; + __le32 Mode; + __le32 AlignmentRequirement; + __le32 FileNameLength; + union { + char __pad; /* Legacy structure padding */ + DECLARE_FLEX_ARRAY(char, FileName); + }; +} __packed; /* level 18 Query */ + +/* See MS-FSCC 2.4.7 */ +typedef struct file_basic_info { /* data block encoding of response to level 18 */ + __le64 CreationTime; + __le64 LastAccessTime; + __le64 LastWriteTime; + __le64 ChangeTime; + __le32 Attributes; + __u32 Pad; +} __packed FILE_BASIC_INFO; /* size info, level 0x101 */ + /* See MS-FSCC 2.4.8 */ typedef struct { __le32 NextEntryOffset; @@ -46,6 +260,11 @@ typedef struct { char FileName[]; } __packed FILE_DIRECTORY_INFO; /* level 0x101 FF resp data */ +/* See MS-FSCC 2.4.13 */ +struct smb2_file_eof_info { /* encoding of request for level 10 */ + __le64 EndOfFile; /* new end of file value */ +} __packed; /* level 20 Set */ + /* See MS-FSCC 2.4.14 */ typedef struct { __le32 NextEntryOffset; @@ -80,6 +299,26 @@ typedef struct { char FileName[]; } __packed FILE_ID_FULL_DIR_INFO; /* level 0x105 FF rsp data */ +/* See MS-FSCC 2.4.27 */ +struct smb2_file_internal_info { + __le64 IndexNumber; +} __packed; /* level 6 Query */ + +/* See MS-FSCC 2.4.28.2 */ +struct smb2_file_link_info { /* encoding of request for level 11 */ + /* New members MUST be added within the struct_group() macro below. */ + __struct_group(smb2_file_link_info_hdr, __hdr, __packed, + __u8 ReplaceIfExists; /* 1 = replace existing link with new */ + /* 0 = fail if link already exists */ + __u8 Reserved[7]; + __u64 RootDirectory; /* MBZ for network operations (why says spec?) */ + __le32 FileNameLength; + ); + char FileName[]; /* Name to be assigned to new link */ +} __packed; /* level 11 Set */ +static_assert(offsetof(struct smb2_file_link_info, FileName) == sizeof(struct smb2_file_link_info_hdr), + "struct member likely outside of __struct_group()"); + /* See MS-FSCC 2.4.34 */ struct smb2_file_network_open_info { struct_group_attr(network_open_info, __packed, @@ -94,6 +333,37 @@ struct smb2_file_network_open_info { __le32 Reserved; } __packed; /* level 34 Query also similar returned in close rsp and open rsp */ +/* See MS-FSCC 2.4.42.2 */ +struct smb2_file_rename_info { /* encoding of request for level 10 */ + /* New members MUST be added within the struct_group() macro below. */ + __struct_group(smb2_file_rename_info_hdr, __hdr, __packed, + __u8 ReplaceIfExists; /* 1 = replace existing target with new */ + /* 0 = fail if target already exists */ + __u8 Reserved[7]; + __u64 RootDirectory; /* MBZ for network operations (why says spec?) */ + __le32 FileNameLength; + ); + char FileName[]; /* New name to be assigned */ + /* padding - overall struct size must be >= 24 so filename + pad >= 6 */ +} __packed; /* level 10 Set */ +static_assert(offsetof(struct smb2_file_rename_info, FileName) == sizeof(struct smb2_file_rename_info_hdr), + "struct member likely outside of __struct_group()"); + +/* File System Information Classes */ +/* See MS-FSCC 2.5 */ +#define FS_VOLUME_INFORMATION 1 /* Query */ +#define FS_LABEL_INFORMATION 2 /* Set */ +#define FS_SIZE_INFORMATION 3 /* Query */ +#define FS_DEVICE_INFORMATION 4 /* Query */ +#define FS_ATTRIBUTE_INFORMATION 5 /* Query */ +#define FS_CONTROL_INFORMATION 6 /* Query, Set */ +#define FS_FULL_SIZE_INFORMATION 7 /* Query */ +#define FS_OBJECT_ID_INFORMATION 8 /* Query, Set */ +#define FS_DRIVER_PATH_INFORMATION 9 /* Query */ +#define FS_SECTOR_SIZE_INFORMATION 11 /* SMB3 or later. Query */ +/* See POSIX Extensions to MS-FSCC 2.3.1.1 */ +#define FS_POSIX_INFORMATION 100 /* SMB3.1.1 POSIX. Query */ + /* See MS-FSCC 2.5.1 */ #define MAX_FS_NAME_LEN 52 typedef struct { @@ -130,6 +400,45 @@ typedef struct { #define FILE_CASE_PRESERVED_NAMES 0x00000002 #define FILE_CASE_SENSITIVE_SEARCH 0x00000001 +/* + * File System Control Information + * See MS-FSCC 2.5.2 + */ +struct smb2_fs_control_info { + __le64 FreeSpaceStartFiltering; + __le64 FreeSpaceThreshold; + __le64 FreeSpaceStopFiltering; + __le64 DefaultQuotaThreshold; + __le64 DefaultQuotaLimit; + __le32 FileSystemControlFlags; + __le32 Padding; +} __packed; + +/* See MS-FSCC 2.5.4 */ +struct smb2_fs_full_size_info { + __le64 TotalAllocationUnits; + __le64 CallerAvailableAllocationUnits; + __le64 ActualAvailableAllocationUnits; + __le32 SectorsPerAllocationUnit; + __le32 BytesPerSector; +} __packed; + +/* See MS-FSCC 2.5.7 */ +#define SSINFO_FLAGS_ALIGNED_DEVICE 0x00000001 +#define SSINFO_FLAGS_PARTITION_ALIGNED_ON_DEVICE 0x00000002 +#define SSINFO_FLAGS_NO_SEEK_PENALTY 0x00000004 +#define SSINFO_FLAGS_TRIM_ENABLED 0x00000008 +/* sector size info struct */ +struct smb3_fs_ss_info { + __le32 LogicalBytesPerSector; + __le32 PhysicalBytesPerSectorForAtomicity; + __le32 PhysicalBytesPerSectorForPerf; + __le32 FSEffPhysicalBytesPerSectorForAtomicity; + __le32 Flags; + __le32 ByteOffsetForSectorAlignment; + __le32 ByteOffsetForPartitionAlignment; +} __packed; + /* See MS-FSCC 2.5.8 */ typedef struct { __le64 TotalAllocationUnits; @@ -138,6 +447,17 @@ typedef struct { __le32 BytesPerSector; } __packed FILE_SYSTEM_SIZE_INFO; /* size info, level 0x103 */ +/* volume info struct - see MS-FSCC 2.5.9 */ +#define MAX_VOL_LABEL_LEN 32 +struct filesystem_vol_info { + __le64 VolumeCreationTime; + __le32 VolumeSerialNumber; + __le32 VolumeLabelLength; /* includes trailing null */ + __u8 SupportsObjects; /* True if eg like NTFS, supports objects */ + __u8 Reserved; + __u8 VolumeLabel[]; /* variable len */ +} __packed; + /* See MS-FSCC 2.5.10 */ typedef struct { __le32 DeviceType; @@ -189,6 +509,22 @@ typedef struct { #define FILE_ATTRIBUTE_NO_SCRUB_DATA_LE cpu_to_le32(FILE_ATTRIBUTE_NO_SCRUB_DATA) #define FILE_ATTRIBUTE_MASK_LE cpu_to_le32(FILE_ATTRIBUTE_MASK) +/* + * SMB2 Notify Action Flags + * See MS-FSCC 2.7.1 + */ +#define FILE_ACTION_ADDED 0x00000001 +#define FILE_ACTION_REMOVED 0x00000002 +#define FILE_ACTION_MODIFIED 0x00000003 +#define FILE_ACTION_RENAMED_OLD_NAME 0x00000004 +#define FILE_ACTION_RENAMED_NEW_NAME 0x00000005 +#define FILE_ACTION_ADDED_STREAM 0x00000006 +#define FILE_ACTION_REMOVED_STREAM 0x00000007 +#define FILE_ACTION_MODIFIED_STREAM 0x00000008 +#define FILE_ACTION_REMOVED_BY_DELETE 0x00000009 +#define FILE_ACTION_ID_NOT_TUNNELLED 0x0000000A +#define FILE_ACTION_TUNNELLED_ID_COLLISION 0x0000000B + /* * Response contains array of the following structures * See MS-FSCC 2.7.1 diff --git a/fs/smb/common/smb2pdu.h b/fs/smb/common/smb2pdu.h index e482c86ceb00d2..85a4248d4f29d9 100644 --- a/fs/smb/co ... [truncated]
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