From: "Jason A. Donenfeld" Jason@zx2c4.com
stable inclusion from stable-v5.10.119 commit 47f0e89b71e281a659c34824176f19d58a003c2d category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5L6BB
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 64276a9939ff414f2f0db38036cf4e1a0a703394 upstream.
Rather than hard coding various lengths, we can use the right constants. Strings should be `char *` while buffers should be `u8 *`. Rather than have a nonsensical and unused maxlength, just remove it. Finally, use snprintf instead of sprintf, just out of good hygiene.
As well, remove the old comment about returning a binary UUID via the binary sysctl syscall. That syscall was removed from the kernel in 5.5, and actually, the "uuid_strategy" function and related infrastructure for even serving it via the binary sysctl syscall was removed with 894d2491153a ("sysctl drivers: Remove dead binary sysctl support") back in 2.6.33.
Reviewed-by: Dominik Brodowski linux@dominikbrodowski.net Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Acked-by: Xie XiuQi xiexiuqi@huawei.com --- drivers/char/random.c | 29 +++++++++++++---------------- 1 file changed, 13 insertions(+), 16 deletions(-)
diff --git a/drivers/char/random.c b/drivers/char/random.c index 6a5da2fe2305..9785f78f49ce 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1661,22 +1661,25 @@ const struct file_operations urandom_fops = { static int sysctl_random_min_urandom_seed = 60; static int sysctl_random_write_wakeup_bits = POOL_MIN_BITS; static int sysctl_poolsize = POOL_BITS; -static char sysctl_bootid[16]; +static u8 sysctl_bootid[UUID_SIZE];
/* * This function is used to return both the bootid UUID, and random - * UUID. The difference is in whether table->data is NULL; if it is, + * UUID. The difference is in whether table->data is NULL; if it is, * then a new UUID is generated and returned to the user. - * - * If the user accesses this via the proc interface, the UUID will be - * returned as an ASCII string in the standard UUID format; if via the - * sysctl system call, as 16 bytes of binary data. */ static int proc_do_uuid(struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos) { - struct ctl_table fake_table; - unsigned char buf[64], tmp_uuid[16], *uuid; + u8 tmp_uuid[UUID_SIZE], *uuid; + char uuid_string[UUID_STRING_LEN + 1]; + struct ctl_table fake_table = { + .data = uuid_string, + .maxlen = UUID_STRING_LEN + }; + + if (write) + return -EPERM;
uuid = table->data; if (!uuid) { @@ -1691,12 +1694,8 @@ static int proc_do_uuid(struct ctl_table *table, int write, void *buffer, spin_unlock(&bootid_spinlock); }
- sprintf(buf, "%pU", uuid); - - fake_table.data = buf; - fake_table.maxlen = sizeof(buf); - - return proc_dostring(&fake_table, write, buffer, lenp, ppos); + snprintf(uuid_string, sizeof(uuid_string), "%pU", uuid); + return proc_dostring(&fake_table, 0, buffer, lenp, ppos); }
extern struct ctl_table random_table[]; @@ -1732,13 +1731,11 @@ struct ctl_table random_table[] = { { .procname = "boot_id", .data = &sysctl_bootid, - .maxlen = 16, .mode = 0444, .proc_handler = proc_do_uuid, }, { .procname = "uuid", - .maxlen = 16, .mode = 0444, .proc_handler = proc_do_uuid, },