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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id t21-20020a635355000000b0043c9da02729sm210127pgl.6.2022.10.13.15.36.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 13 Oct 2022 15:36:55 -0700 (PDT) From: Kees Cook To: Mimi Zohar Cc: Kees Cook , Dmitry Kasatkin , Paul Moore , James Morris , "Serge E. Hallyn" , Borislav Petkov , Jonathan McDowell , Takashi Iwai , Petr Vorel , linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , KP Singh , Casey Schaufler , John Johansen , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH 3/9] ima: Move xattr hooks into LSM Date: Thu, 13 Oct 2022 15:36:48 -0700 Message-Id: <20221013223654.659758-3-keescook@chromium.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20221013222702.never.990-kees@kernel.org> References: <20221013222702.never.990-kees@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=7063; h=from:subject; bh=UwVZQhUAV34kLZLvWg3gW0Y3AxAoqPtrDDTwL+QIuyQ=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBjSJMEHh/BpJ8T/UrB3miOUYuzJYjTTQP/es9Hk0XI dfZG4xuJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCY0iTBAAKCRCJcvTf3G3AJpZ/EA CGzX2dABmN4vM8z88raKKj3Nl+cOZLLMTHDR3tYm9/U+nievEWZnBIMlbRSDXwjwhv8yOEwkXHomUz EOhnf8FmyzCzjBzXnEacLLLfu6c+5Saz5VuJI11paPu8IUUHHbI8A2c2OOjXaunaJ0pNAuWBpzwIjJ nSNOFNj20t+3vJ/urzKa9/Pqyg8zDHFD9qqpqaBtGGoUwjY3m7XrMqpeKtruZlJUoixyAKUCBR2G+E qW868F9IuhZf12kNaRzP9ehAlWXDreKSeD9GCy8U4uy/FxHNU0llHWLXPJlznr6rSrOov5sVsAOh4Q 92NaFx4RN8V24y4Bkgxkr36IkQ+5+x4uVSNvPGIUVme+c2kVGxGFf9Z5IfDxgYkbyPBl64CF3alsB7 9Jcz7EIvyrYTFXKJapKa3vqpUrdC7L1TJrBfC8OGD2a3nk1E/Z73ZX6TKvIDfOwqY+0SP9s+ptf76q F1AL5hiY+SDsmrM8Q1aWF+Z95WVrcbfNJNezm6/hS9xn3IEeeEdiDeugPyFCMHbzxJ4Zu+GXw+rgPB aoYvjD+300H3Q//lbzYWmc3NCxS0rEwy44q2AQ+r+uqoAMcaa3j3YrJdYPCRearUIv1xpNBoeAzUtb Lr7vob6z1IlkP5lAd+cjBvbd9IbQKJNYK/WtqiqjtVs8HzFa6aaYPjxGpRYw== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org Move the xattr IMA hooks into normal LSM layer. As with SELinux and Smack, handle calling cap_inode_setxattr() internally. Cc: Mimi Zohar Cc: Dmitry Kasatkin Cc: Paul Moore Cc: James Morris Cc: "Serge E. Hallyn" Cc: Borislav Petkov Cc: Jonathan McDowell Cc: Takashi Iwai Cc: Petr Vorel Cc: linux-integrity@vger.kernel.org Cc: linux-security-module@vger.kernel.org Signed-off-by: Kees Cook --- include/linux/ima.h | 16 ---------------- security/integrity/ima/ima.h | 10 ++++++++++ security/integrity/ima/ima_appraise.c | 19 ++++++++++++++++--- security/integrity/ima/ima_main.c | 4 ++++ security/security.c | 10 ++-------- 5 files changed, 32 insertions(+), 27 deletions(-) diff --git a/include/linux/ima.h b/include/linux/ima.h index 3c641cc65270..6dc5143f89f2 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -135,9 +135,6 @@ static inline void ima_post_key_create_or_update(struct key *keyring, extern bool is_ima_appraise_enabled(void); extern void ima_inode_post_setattr(struct user_namespace *mnt_userns, struct dentry *dentry); -extern int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name, - const void *xattr_value, size_t xattr_value_len); -extern int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name); #else static inline bool is_ima_appraise_enabled(void) { @@ -150,19 +147,6 @@ static inline void ima_inode_post_setattr(struct user_namespace *mnt_userns, return; } -static inline int ima_inode_setxattr(struct dentry *dentry, - const char *xattr_name, - const void *xattr_value, - size_t xattr_value_len) -{ - return 0; -} - -static inline int ima_inode_removexattr(struct dentry *dentry, - const char *xattr_name) -{ - return 0; -} #endif /* CONFIG_IMA_APPRAISE */ #if defined(CONFIG_IMA_APPRAISE) && defined(CONFIG_INTEGRITY_TRUSTED_KEYRING) diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index be965a8715e4..15a369df4c00 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -168,6 +168,16 @@ int __init ima_init_digests(void); int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event, void *lsm_data); +/* LSM hooks */ +#ifdef CONFIG_IMA_APPRAISE +int ima_inode_setxattr(struct user_namespace *mnt_userns, + struct dentry *dentry, const char *xattr_name, + const void *xattr_value, size_t xattr_value_len, + int flags); +int ima_inode_removexattr(struct user_namespace *mnt_userns, + struct dentry *dentry, const char *xattr_name); +#endif + /* * used to protect h_table and sha_table */ diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c index bde74fcecee3..ddd9df6b7dac 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -744,8 +744,10 @@ static int validate_hash_algo(struct dentry *dentry, return -EACCES; } -int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name, - const void *xattr_value, size_t xattr_value_len) +int ima_inode_setxattr(struct user_namespace *mnt_userns, + struct dentry *dentry, const char *xattr_name, + const void *xattr_value, size_t xattr_value_len, + int flags) { const struct evm_ima_xattr_data *xvalue = xattr_value; int digsig = 0; @@ -754,6 +756,11 @@ int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name, result = ima_protect_xattr(dentry, xattr_name, xattr_value, xattr_value_len); if (result == 1) { + result = cap_inode_setxattr(dentry, xattr_name, xattr_value, + xattr_value_len, flags); + if (result) + return result; + if (!xattr_value_len || (xvalue->type >= IMA_XATTR_LAST)) return -EINVAL; digsig = (xvalue->type == EVM_IMA_XATTR_DIGSIG); @@ -770,11 +777,17 @@ int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name, return result; } -int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name) +int ima_inode_removexattr(struct user_namespace *mnt_userns, + struct dentry *dentry, const char *xattr_name) { int result; result = ima_protect_xattr(dentry, xattr_name, NULL, 0); + if (result == 1) { + result = cap_inode_removexattr(mnt_userns, dentry, xattr_name); + if (result) + return result; + } if (result == 1 || evm_revalidate_status(xattr_name)) { ima_reset_appraise_flags(d_backing_inode(dentry), 0); if (result == 1) diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 2cff001b02e4..b3b79d030a67 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -1089,6 +1089,10 @@ static struct security_hook_list ima_hooks[] __lsm_ro_after_init = { LSM_HOOK_INIT(kernel_post_read_file, ima_post_read_file), LSM_HOOK_INIT(kernel_load_data, ima_load_data), LSM_HOOK_INIT(kernel_post_load_data, ima_post_load_data), +#ifdef CONFIG_IMA_APPRAISE + LSM_HOOK_INIT(inode_setxattr, ima_inode_setxattr), + LSM_HOOK_INIT(inode_removexattr, ima_inode_removexattr), +#endif }; void __init integrity_lsm_ima_init(void) diff --git a/security/security.c b/security/security.c index 8f7c1b5fa5fa..ca731132a0e9 100644 --- a/security/security.c +++ b/security/security.c @@ -1349,7 +1349,7 @@ int security_inode_setxattr(struct user_namespace *mnt_userns, if (unlikely(IS_PRIVATE(d_backing_inode(dentry)))) return 0; /* - * SELinux and Smack integrate the cap call, + * SELinux, Smack, and IMA integrate the cap call, * so assume that all LSMs supplying this call do so. */ ret = call_int_hook(inode_setxattr, 1, mnt_userns, dentry, name, value, @@ -1357,9 +1357,6 @@ int security_inode_setxattr(struct user_namespace *mnt_userns, if (ret == 1) ret = cap_inode_setxattr(dentry, name, value, size, flags); - if (ret) - return ret; - ret = ima_inode_setxattr(dentry, name, value, size); if (ret) return ret; return evm_inode_setxattr(mnt_userns, dentry, name, value, size); @@ -1396,15 +1393,12 @@ int security_inode_removexattr(struct user_namespace *mnt_userns, if (unlikely(IS_PRIVATE(d_backing_inode(dentry)))) return 0; /* - * SELinux and Smack integrate the cap call, + * SELinux, Smack, and IMA integrate the cap call, * so assume that all LSMs supplying this call do so. */ ret = call_int_hook(inode_removexattr, 1, mnt_userns, dentry, name); if (ret == 1) ret = cap_inode_removexattr(mnt_userns, dentry, name); - if (ret) - return ret; - ret = ima_inode_removexattr(dentry, name); if (ret) return ret; return evm_inode_removexattr(mnt_userns, dentry, name);