From f5507aefc9114ced49d1ee527f63ea12ff5d7751 Mon Sep 17 00:00:00 2001 From: Thorsten Blum Date: Thu, 4 Sep 2025 13:40:29 +0200 Subject: [PATCH] s390/debug: Replace kmalloc() + copy_from_user() with memdup_user_nul() Replace kmalloc() followed by copy_from_user() with memdup_user_nul() to improve and simplify debug_get_user_string(). Remove the manual NUL-termination. No functional changes intended. Signed-off-by: Thorsten Blum Reviewed-by: Niklas Schnelle Signed-off-by: Alexander Gordeev --- arch/s390/kernel/debug.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) diff --git a/arch/s390/kernel/debug.c b/arch/s390/kernel/debug.c index c62100dc62c8d..6a26f202441d3 100644 --- a/arch/s390/kernel/debug.c +++ b/arch/s390/kernel/debug.c @@ -1416,18 +1416,12 @@ static inline char *debug_get_user_string(const char __user *user_buf, { char *buffer; - buffer = kmalloc(user_len + 1, GFP_KERNEL); - if (!buffer) - return ERR_PTR(-ENOMEM); - if (copy_from_user(buffer, user_buf, user_len) != 0) { - kfree(buffer); - return ERR_PTR(-EFAULT); - } + buffer = memdup_user_nul(user_buf, user_len); + if (IS_ERR(buffer)) + return buffer; /* got the string, now strip linefeed. */ if (buffer[user_len - 1] == '\n') buffer[user_len - 1] = 0; - else - buffer[user_len] = 0; return buffer; } -- 2.47.3