Add a keyctl function that requests a set of capability bits to find out what features are supported.
Signed-off-by: David Howells <[email protected]> --- include/uapi/linux/keyctl.h | 14 ++++++++++++++ security/keys/compat.c | 3 +++ security/keys/internal.h | 2 ++ security/keys/keyctl.c | 37 +++++++++++++++++++++++++++++++++++++ 4 files changed, 56 insertions(+) diff --git a/include/uapi/linux/keyctl.h b/include/uapi/linux/keyctl.h index fd9fb11b312b..aa4972163442 100644 --- a/include/uapi/linux/keyctl.h +++ b/include/uapi/linux/keyctl.h @@ -68,6 +68,7 @@ #define KEYCTL_PKEY_VERIFY 28 /* Verify a public key signature */ #define KEYCTL_RESTRICT_KEYRING 29 /* Restrict keys allowed to link to a keyring */ #define KEYCTL_MOVE 30 /* Move keys between keyrings */ +#define KEYCTL_CAPABILITIES 31 /* Find capabilities of keyrings subsystem */ /* keyctl structures */ struct keyctl_dh_params { @@ -115,4 +116,17 @@ struct keyctl_pkey_params { #define KEYCTL_MOVE_EXCL 0x00000001 /* Do not displace from the to-keyring */ +/* + * Capabilities flags. The capabilities list is an array of 32-bit integers; + * each integer can carry up to 32 flags. + */ +#define KEYCTL_CAPS0_CAPABILITIES 0x00000001 /* KEYCTL_CAPABILITIES supported */ +#define KEYCTL_CAPS0_PERSISTENT_KEYRINGS 0x00000002 /* Persistent keyrings enabled */ +#define KEYCTL_CAPS0_DIFFIE_HELLMAN 0x00000004 /* Diffie-Hellman computation enabled */ +#define KEYCTL_CAPS0_PUBLIC_KEY 0x00000008 /* Public key ops enabled */ +#define KEYCTL_CAPS0_BIG_KEY 0x00000010 /* big_key-type enabled */ +#define KEYCTL_CAPS0_INVALIDATE 0x00000020 /* KEYCTL_INVALIDATE supported */ +#define KEYCTL_CAPS0_RESTRICT_KEYRING 0x00000040 /* KEYCTL_RESTRICT_KEYRING supported */ +#define KEYCTL_CAPS0_MOVE 0x00000080 /* KEYCTL_MOVE supported */ + #endif /* _LINUX_KEYCTL_H */ diff --git a/security/keys/compat.c b/security/keys/compat.c index b326bc4f84d7..a53e30da20c5 100644 --- a/security/keys/compat.c +++ b/security/keys/compat.c @@ -162,6 +162,9 @@ COMPAT_SYSCALL_DEFINE5(keyctl, u32, option, case KEYCTL_MOVE: return keyctl_keyring_move(arg2, arg3, arg4, arg5); + case KEYCTL_CAPABILITIES: + return keyctl_capabilities(compat_ptr(arg2), arg3); + default: return -EOPNOTSUPP; } diff --git a/security/keys/internal.h b/security/keys/internal.h index b54a58c025ae..884fd796f668 100644 --- a/security/keys/internal.h +++ b/security/keys/internal.h @@ -329,6 +329,8 @@ static inline long keyctl_pkey_e_d_s(int op, } #endif +extern long keyctl_capabilities(unsigned int __user *_buffer, size_t buflen); + /* * Debugging key validation */ diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c index bbfe7d92d41c..b3db363e0b25 100644 --- a/security/keys/keyctl.c +++ b/security/keys/keyctl.c @@ -30,6 +30,18 @@ #define KEY_MAX_DESC_SIZE 4096 +static const u32 keyrings_capabilities[1] = { + [0] = (KEYCTL_CAPS0_CAPABILITIES | + (IS_ENABLED(CONFIG_PERSISTENT_KEYRINGS) ? KEYCTL_CAPS0_PERSISTENT_KEYRINGS : 0) | + (IS_ENABLED(CONFIG_KEY_DH_OPERATIONS) ? KEYCTL_CAPS0_DIFFIE_HELLMAN : 0) | + (IS_ENABLED(CONFIG_ASYMMETRIC_KEY_TYPE) ? KEYCTL_CAPS0_PUBLIC_KEY : 0) | + (IS_ENABLED(CONFIG_BIG_KEYS) ? KEYCTL_CAPS0_BIG_KEY : 0) | + KEYCTL_CAPS0_INVALIDATE | + KEYCTL_CAPS0_RESTRICT_KEYRING | + KEYCTL_CAPS0_MOVE + ), +}; + static int key_get_type_from_user(char *type, const char __user *_type, unsigned len) @@ -1678,6 +1690,28 @@ long keyctl_restrict_keyring(key_serial_t id, const char __user *_type, return ret; } +/* + * Get keyrings subsystem capabilities. + */ +long keyctl_capabilities(unsigned int __user *_buffer, size_t buflen) +{ + size_t size = buflen; + + if (size == 0) + return sizeof(keyrings_capabilities); + if (size & 3) + return -EINVAL; + if (size > sizeof(keyrings_capabilities)) + size = sizeof(keyrings_capabilities); + if (copy_to_user(_buffer, keyrings_capabilities, size) != 0) + return -EFAULT; + if (size < buflen && + clear_user(_buffer + size, buflen - size) != 0) + return -EFAULT; + + return sizeof(keyrings_capabilities); +} + /* * The key control system call */ @@ -1824,6 +1858,9 @@ SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3, (key_serial_t)arg4, (unsigned int)arg5); + case KEYCTL_CAPABILITIES: + return keyctl_capabilities((unsigned int __user *)arg2, (size_t)arg3); + default: return -EOPNOTSUPP; }
