From f2156d35c9584a4afdb71de4bc24b3fef674a63d Mon Sep 17 00:00:00 2001 From: Shyam Prasad N Date: Mon, 9 Nov 2020 06:12:49 -0800 Subject: [PATCH] cifs: Enable sticky bit with cifsacl mount option. For the cifsacl mount option, we did not support sticky bits. With this patch, we do support it, by setting the DELETE_CHILD perm on the directory only for the owner user. When sticky bit is not enabled, allow DELETE_CHILD perm for everyone. Signed-off-by: Shyam Prasad N Signed-off-by: Steve French --- fs/cifs/cifsacl.c | 41 ++++++++++++++++++++++++++++++----------- fs/cifs/cifsacl.h | 4 ++++ fs/cifs/cifspdu.h | 2 +- 3 files changed, 35 insertions(+), 12 deletions(-) diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c index 9b7f727b0e88..c3954bfcb666 100644 --- a/fs/cifs/cifsacl.c +++ b/fs/cifs/cifsacl.c @@ -617,6 +617,17 @@ static void access_flags_to_mode(__le32 ace_flags, int type, umode_t *pmode, !(*pdenied & mask & 0111)) *pmode |= mask & 0111; + /* If DELETE_CHILD is set only on an owner ACE, set sticky bit */ + if (flags & FILE_DELETE_CHILD) { + if (mask == ACL_OWNER_MASK) { + if (!(*pdenied & 01000)) + *pmode |= 01000; + } else if (!(*pdenied & 01000)) { + *pmode &= ~01000; + *pdenied |= 01000; + } + } + cifs_dbg(NOISY, "access flags 0x%x mode now %04o\n", flags, *pmode); return; } @@ -652,7 +663,9 @@ static void mode_to_access_flags(umode_t mode, umode_t bits_to_use, } static __u16 fill_ace_for_sid(struct cifs_ace *pntace, - const struct cifs_sid *psid, __u64 nmode, umode_t bits, __u8 access_type) + const struct cifs_sid *psid, __u64 nmode, + umode_t bits, __u8 access_type, + bool allow_delete_child) { int i; __u16 size = 0; @@ -661,10 +674,15 @@ static __u16 fill_ace_for_sid(struct cifs_ace *pntace, pntace->type = access_type; pntace->flags = 0x0; mode_to_access_flags(nmode, bits, &access_req); + + if (access_type == ACCESS_ALLOWED && allow_delete_child) + access_req |= FILE_DELETE_CHILD; + if (access_type == ACCESS_ALLOWED && !access_req) access_req = SET_MINIMUM_RIGHTS; else if (access_type == ACCESS_DENIED) access_req &= ~SET_MINIMUM_RIGHTS; + pntace->access_req = cpu_to_le32(access_req); pntace->sid.revision = psid->revision; @@ -717,10 +735,6 @@ static void dump_ace(struct cifs_ace *pace, char *end_of_acl) } #endif -#define ACL_OWNER_MASK 0700 -#define ACL_GROUP_MASK 0770 -#define ACL_EVERYONE_MASK 0777 - static void parse_dacl(struct cifs_acl *pdacl, char *end_of_acl, struct cifs_sid *pownersid, struct cifs_sid *pgrpsid, struct cifs_fattr *fattr, bool mode_from_special_sid) @@ -904,6 +918,7 @@ static int set_chmod_dacl(struct cifs_acl *pndacl, struct cifs_sid *pownersid, __u64 other_mode; __u64 deny_user_mode = 0; __u64 deny_group_mode = 0; + bool sticky_set = false; pnndacl = (struct cifs_acl *)((char *)pndacl + sizeof(struct cifs_acl)); @@ -945,31 +960,35 @@ static int set_chmod_dacl(struct cifs_acl *pndacl, struct cifs_sid *pownersid, *pnmode = user_mode | group_mode | other_mode | (nmode & ~0777); + /* This tells if we should allow delete child for group and everyone. */ + if (nmode & 01000) + sticky_set = true; + if (deny_user_mode) { size += fill_ace_for_sid((struct cifs_ace *)((char *)pnndacl + size), - pownersid, deny_user_mode, 0700, ACCESS_DENIED); + pownersid, deny_user_mode, 0700, ACCESS_DENIED, false); num_aces++; } /* Group DENY ACE does not conflict with owner ALLOW ACE. Keep in preferred order*/ if (deny_group_mode && !(deny_group_mode & (user_mode >> 3))) { size += fill_ace_for_sid((struct cifs_ace *)((char *)pnndacl + size), - pgrpsid, deny_group_mode, 0070, ACCESS_DENIED); + pgrpsid, deny_group_mode, 0070, ACCESS_DENIED, false); num_aces++; } size += fill_ace_for_sid((struct cifs_ace *) ((char *)pnndacl + size), - pownersid, user_mode, 0700, ACCESS_ALLOWED); + pownersid, user_mode, 0700, ACCESS_ALLOWED, true); num_aces++; /* Group DENY ACE conflicts with owner ALLOW ACE. So keep it after. */ if (deny_group_mode && (deny_group_mode & (user_mode >> 3))) { size += fill_ace_for_sid((struct cifs_ace *)((char *)pnndacl + size), - pgrpsid, deny_group_mode, 0070, ACCESS_DENIED); + pgrpsid, deny_group_mode, 0070, ACCESS_DENIED, false); num_aces++; } size += fill_ace_for_sid((struct cifs_ace *)((char *)pnndacl + size), - pgrpsid, group_mode, 0070, ACCESS_ALLOWED); + pgrpsid, group_mode, 0070, ACCESS_ALLOWED, !sticky_set); num_aces++; size += fill_ace_for_sid((struct cifs_ace *)((char *)pnndacl + size), - &sid_everyone, other_mode, 0007, ACCESS_ALLOWED); + &sid_everyone, other_mode, 0007, ACCESS_ALLOWED, !sticky_set); num_aces++; set_size: diff --git a/fs/cifs/cifsacl.h b/fs/cifs/cifsacl.h index 45665ff87b64..ff7fd0862e28 100644 --- a/fs/cifs/cifsacl.h +++ b/fs/cifs/cifsacl.h @@ -30,6 +30,10 @@ #define WRITE_BIT 0x2 #define EXEC_BIT 0x1 +#define ACL_OWNER_MASK 0700 +#define ACL_GROUP_MASK 0770 +#define ACL_EVERYONE_MASK 0777 + #define UBITSHIFT 6 #define GBITSHIFT 3 diff --git a/fs/cifs/cifspdu.h b/fs/cifs/cifspdu.h index 593d826820c3..ce51183ecaf4 100644 --- a/fs/cifs/cifspdu.h +++ b/fs/cifs/cifspdu.h @@ -262,7 +262,7 @@ | WRITE_OWNER | SYNCHRONIZE) #define SET_FILE_WRITE_RIGHTS (FILE_WRITE_DATA | FILE_APPEND_DATA \ | FILE_READ_EA | FILE_WRITE_EA \ - | FILE_DELETE_CHILD | FILE_READ_ATTRIBUTES \ + | FILE_READ_ATTRIBUTES \ | FILE_WRITE_ATTRIBUTES \ | DELETE | READ_CONTROL | WRITE_DAC \ | WRITE_OWNER | SYNCHRONIZE)