6.6-stable review patch. If anyone has any objections, please let me know.
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From: Mimi Zohar zohar@linux.ibm.com
[ Upstream commit 40ca4ee3136d2d09977d1cab8c0c0e1582c3359d ]
The security.evm HMAC and the original file signatures contain filesystem specific data. As a result, the HMAC and signature are not the same on the stacked and backing filesystems.
Don't copy up 'security.evm'.
Reviewed-by: Amir Goldstein amir73il@gmail.com Reviewed-by: Christian Brauner brauner@kernel.org Signed-off-by: Mimi Zohar zohar@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/evm.h | 6 ++++++ security/integrity/evm/evm_main.c | 7 +++++++ security/security.c | 2 +- 3 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/include/linux/evm.h b/include/linux/evm.h index 01fc495a83e27..36ec884320d9f 100644 --- a/include/linux/evm.h +++ b/include/linux/evm.h @@ -31,6 +31,7 @@ extern void evm_inode_post_setxattr(struct dentry *dentry, const char *xattr_name, const void *xattr_value, size_t xattr_value_len); +extern int evm_inode_copy_up_xattr(const char *name); extern int evm_inode_removexattr(struct mnt_idmap *idmap, struct dentry *dentry, const char *xattr_name); extern void evm_inode_post_removexattr(struct dentry *dentry, @@ -117,6 +118,11 @@ static inline void evm_inode_post_setxattr(struct dentry *dentry, return; }
+static inline int evm_inode_copy_up_xattr(const char *name) +{ + return 0; +} + static inline int evm_inode_removexattr(struct mnt_idmap *idmap, struct dentry *dentry, const char *xattr_name) diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index ff9a939dad8e4..2393230c03aa3 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -864,6 +864,13 @@ void evm_inode_post_setattr(struct dentry *dentry, int ia_valid) evm_update_evmxattr(dentry, NULL, NULL, 0); }
+int evm_inode_copy_up_xattr(const char *name) +{ + if (strcmp(name, XATTR_NAME_EVM) == 0) + return 1; /* Discard */ + return -EOPNOTSUPP; +} + /* * evm_inode_init_security - initializes security.evm HMAC value */ diff --git a/security/security.c b/security/security.c index dd26f21b2244b..b6144833c7a8e 100644 --- a/security/security.c +++ b/security/security.c @@ -2539,7 +2539,7 @@ int security_inode_copy_up_xattr(const char *name) return rc; }
- return LSM_RET_DEFAULT(inode_copy_up_xattr); + return evm_inode_copy_up_xattr(name); } EXPORT_SYMBOL(security_inode_copy_up_xattr);