diff options
| author |   Alexander Gordeev <agordeev@linux.ibm.com> | 2022-07-19 07:16:33 +0200 |
|---|---|---|
| committer | Alexander Gordeev <agordeev@linux.ibm.com> | 2022-07-20 17:21:41 +0200 |
| commit | 9ffed254d938c9e99eb7761c7f739294c84e0367 (patch) | |
| tree | b713b9cbef3fd731e9ee6b02c5d4b453800fabe1 | |
| parent | s390/crash: fix incorrect number of bytes to copy to user space (diff) | |
| download | linux-dev-9ffed254d938c9e99eb7761c7f739294c84e0367.tar.xz linux-dev-9ffed254d938c9e99eb7761c7f739294c84e0367.zip | |
s390/zcore: fix race when reading from hardware system area
Memory buffer used for reading out data from hardware system
area is not protected against concurrent access.
Reported-by: Matthew Wilcox <willy@infradead.org>
Fixes: 411ed3225733 ("[S390] zfcpdump support.")
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Tested-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Link: https://lore.kernel.org/r/e68137f0f9a0d2558f37becc20af18e2939934f6.1658206891.git.agordeev@linux.ibm.com
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
| -rw-r--r-- | drivers/s390/char/zcore.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/s390/char/zcore.c b/drivers/s390/char/zcore.c index 516783ba950f..92b32ce645b9 100644 --- a/drivers/s390/char/zcore.c +++ b/drivers/s390/char/zcore.c @@ -50,6 +50,7 @@ static struct dentry *zcore_reipl_file; static struct dentry *zcore_hsa_file; static struct ipl_parameter_block *zcore_ipl_block; +static DEFINE_MUTEX(hsa_buf_mutex); static char hsa_buf[PAGE_SIZE] __aligned(PAGE_SIZE); /* @@ -66,19 +67,24 @@ int memcpy_hsa_user(void __user *dest, unsigned long src, size_t count) if (!hsa_available) return -ENODATA; + mutex_lock(&hsa_buf_mutex); while (count) { if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) { TRACE("sclp_sdias_copy() failed\n"); + mutex_unlock(&hsa_buf_mutex); return -EIO; } offset = src % PAGE_SIZE; bytes = min(PAGE_SIZE - offset, count); - if (copy_to_user(dest, hsa_buf + offset, bytes)) + if (copy_to_user(dest, hsa_buf + offset, bytes)) { + mutex_unlock(&hsa_buf_mutex); return -EFAULT; + } src += bytes; dest += bytes; count -= bytes; } + mutex_unlock(&hsa_buf_mutex); return 0; } @@ -96,9 +102,11 @@ int memcpy_hsa_kernel(void *dest, unsigned long src, size_t count) if (!hsa_available) return -ENODATA; + mutex_lock(&hsa_buf_mutex); while (count) { if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) { TRACE("sclp_sdias_copy() failed\n"); + mutex_unlock(&hsa_buf_mutex); return -EIO; } offset = src % PAGE_SIZE; @@ -108,6 +116,7 @@ int memcpy_hsa_kernel(void *dest, unsigned long src, size_t count) dest += bytes; count -= bytes; } + mutex_unlock(&hsa_buf_mutex); return 0; } |