Backport the following upstream commit into Linux v5.19.y:
commit dd9373402280cf4715fdc8fd5070f7d039e43511 Author: Casey Schaufler casey@schaufler-ca.com Date: Tue Aug 23 16:46:18 2022 -0700
Smack: Provide read control for io_uring_cmd
Limit io_uring "cmd" options to files for which the caller has Smack read access. There may be cases where the cmd option may be closer to a write access than a read, but there is no way to make that determination.
Signed-off-by: Paul Moore paul@paul-moore.com --- security/smack/smack_lsm.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+)
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 6207762dbdb1..b30e20f64471 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -42,6 +42,7 @@ #include <linux/fs_context.h> #include <linux/fs_parser.h> #include <linux/watch_queue.h> +#include <linux/io_uring.h> #include "smack.h"
#define TRANS_TRUE "TRUE" @@ -4739,6 +4740,36 @@ static int smack_uring_sqpoll(void) return -EPERM; }
+/** + * smack_uring_cmd - check on file operations for io_uring + * @ioucmd: the command in question + * + * Make a best guess about whether a io_uring "command" should + * be allowed. Use the same logic used for determining if the + * file could be opened for read in the absence of better criteria. + */ +static int smack_uring_cmd(struct io_uring_cmd *ioucmd) +{ + struct file *file = ioucmd->file; + struct smk_audit_info ad; + struct task_smack *tsp; + struct inode *inode; + int rc; + + if (!file) + return -EINVAL; + + tsp = smack_cred(file->f_cred); + inode = file_inode(file); + + smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH); + smk_ad_setfield_u_fs_path(&ad, file->f_path); + rc = smk_tskacc(tsp, smk_of_inode(inode), MAY_READ, &ad); + rc = smk_bu_credfile(file->f_cred, file, MAY_READ, rc); + + return rc; +} + #endif /* CONFIG_IO_URING */
struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = { @@ -4896,6 +4927,7 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = { #ifdef CONFIG_IO_URING LSM_HOOK_INIT(uring_override_creds, smack_uring_override_creds), LSM_HOOK_INIT(uring_sqpoll, smack_uring_sqpoll), + LSM_HOOK_INIT(uring_cmd, smack_uring_cmd), #endif };