From c3367a1b47d590f97109cd4b5189e750fb26c0f1 Mon Sep 17 00:00:00 2001 From: "Steven J. Magnani" Date: Tue, 27 Aug 2019 07:13:59 -0500 Subject: [PATCH] udf: augment UDF permissions on new inodes Windows presents files created within Linux as read-only, even when permissions in Linux indicate the file should be writable. UDF defines a slightly different set of basic file permissions than Linux. Specifically, UDF has "delete" and "change attribute" permissions for each access class (user/group/other). Linux has no equivalents for these. When the Linux UDF driver creates a file (or directory), no UDF delete or change attribute permissions are granted. The lack of delete permission appears to cause Windows to mark an item read-only when its permissions otherwise indicate that it should be read-write. Fix this by having UDF delete permissions track Linux write permissions. Also grant UDF change attribute permission to the owner when creating a new inode. Reported by: Ty Young Signed-off-by: Steven J. Magnani Link: https://lore.kernel.org/r/20190827121359.9954-1-steve@digidescorp.com Signed-off-by: Jan Kara --- fs/udf/file.c | 3 +++ fs/udf/ialloc.c | 3 +++ fs/udf/inode.c | 31 +++++++++++++++++++++++++++---- fs/udf/udf_i.h | 1 + fs/udf/udfdecl.h | 1 + 5 files changed, 35 insertions(+), 4 deletions(-) diff --git a/fs/udf/file.c b/fs/udf/file.c index cd31e4f6d6da..628941a6b79a 100644 --- a/fs/udf/file.c +++ b/fs/udf/file.c @@ -280,6 +280,9 @@ static int udf_setattr(struct dentry *dentry, struct iattr *attr) return error; } + if (attr->ia_valid & ATTR_MODE) + udf_update_extra_perms(inode, attr->ia_mode); + setattr_copy(inode, attr); mark_inode_dirty(inode); return 0; diff --git a/fs/udf/ialloc.c b/fs/udf/ialloc.c index f8e5872f7cc2..0adb40718a5d 100644 --- a/fs/udf/ialloc.c +++ b/fs/udf/ialloc.c @@ -118,6 +118,9 @@ struct inode *udf_new_inode(struct inode *dir, umode_t mode) iinfo->i_lenAlloc = 0; iinfo->i_use = 0; iinfo->i_checkpoint = 1; + iinfo->i_extraPerms = FE_PERM_U_CHATTR; + udf_update_extra_perms(inode, mode); + if (UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_USE_AD_IN_ICB)) iinfo->i_alloc_type = ICBTAG_FLAG_AD_IN_ICB; else if (UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_USE_SHORT_AD)) diff --git a/fs/udf/inode.c b/fs/udf/inode.c index 54eee39f2698..ea80036d7897 100644 --- a/fs/udf/inode.c +++ b/fs/udf/inode.c @@ -45,6 +45,13 @@ #define EXTENT_MERGE_SIZE 5 +#define FE_MAPPED_PERMS (FE_PERM_U_READ | FE_PERM_U_WRITE | FE_PERM_U_EXEC | \ + FE_PERM_G_READ | FE_PERM_G_WRITE | FE_PERM_G_EXEC | \ + FE_PERM_O_READ | FE_PERM_O_WRITE | FE_PERM_O_EXEC) + +#define FE_DELETE_PERMS (FE_PERM_U_DELETE | FE_PERM_G_DELETE | \ + FE_PERM_O_DELETE) + static umode_t udf_convert_permissions(struct fileEntry *); static int udf_update_inode(struct inode *, int); static int udf_sync_inode(struct inode *inode); @@ -1458,6 +1465,8 @@ reread: else inode->i_mode = udf_convert_permissions(fe); inode->i_mode &= ~sbi->s_umask; + iinfo->i_extraPerms = le32_to_cpu(fe->permissions) & ~FE_MAPPED_PERMS; + read_unlock(&sbi->s_cred_lock); link_count = le16_to_cpu(fe->fileLinkCount); @@ -1631,6 +1640,23 @@ static umode_t udf_convert_permissions(struct fileEntry *fe) return mode; } +void udf_update_extra_perms(struct inode *inode, umode_t mode) +{ + struct udf_inode_info *iinfo = UDF_I(inode); + + /* + * UDF 2.01 sec. 3.3.3.3 Note 2: + * In Unix, delete permission tracks write + */ + iinfo->i_extraPerms &= ~FE_DELETE_PERMS; + if (mode & 0200) + iinfo->i_extraPerms |= FE_PERM_U_DELETE; + if (mode & 0020) + iinfo->i_extraPerms |= FE_PERM_G_DELETE; + if (mode & 0002) + iinfo->i_extraPerms |= FE_PERM_O_DELETE; +} + int udf_write_inode(struct inode *inode, struct writeback_control *wbc) { return udf_update_inode(inode, wbc->sync_mode == WB_SYNC_ALL); @@ -1703,10 +1729,7 @@ static int udf_update_inode(struct inode *inode, int do_sync) ((inode->i_mode & 0070) << 2) | ((inode->i_mode & 0700) << 4); - udfperms |= (le32_to_cpu(fe->permissions) & - (FE_PERM_O_DELETE | FE_PERM_O_CHATTR | - FE_PERM_G_DELETE | FE_PERM_G_CHATTR | - FE_PERM_U_DELETE | FE_PERM_U_CHATTR)); + udfperms |= iinfo->i_extraPerms; fe->permissions = cpu_to_le32(udfperms); if (S_ISDIR(inode->i_mode) && inode->i_nlink > 0) diff --git a/fs/udf/udf_i.h b/fs/udf/udf_i.h index 00d773d1b7cf..4245d1f63258 100644 --- a/fs/udf/udf_i.h +++ b/fs/udf/udf_i.h @@ -38,6 +38,7 @@ struct udf_inode_info { __u32 i_next_alloc_block; __u32 i_next_alloc_goal; __u32 i_checkpoint; + __u32 i_extraPerms; unsigned i_alloc_type : 3; unsigned i_efe : 1; /* extendedFileEntry */ unsigned i_use : 1; /* unallocSpaceEntry */ diff --git a/fs/udf/udfdecl.h b/fs/udf/udfdecl.h index 65e243ebeb9c..9dd0814f1077 100644 --- a/fs/udf/udfdecl.h +++ b/fs/udf/udfdecl.h @@ -170,6 +170,7 @@ extern int8_t udf_next_aext(struct inode *, struct extent_position *, struct kernel_lb_addr *, uint32_t *, int); extern int8_t udf_current_aext(struct inode *, struct extent_position *, struct kernel_lb_addr *, uint32_t *, int); +extern void udf_update_extra_perms(struct inode *inode, umode_t mode); /* misc.c */ extern struct buffer_head *udf_tgetblk(struct super_block *sb,