diff options
| author | Alexander Gordeev <agordeev@linux.ibm.com> | 2022-07-19 08:16:33 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-08-25 12:11:25 +0300 |
| commit | db7bc17d33ac1f08d6a9f512eee1a6e13031c968 (patch) | |
| tree | 063a3882de31594b4d8dc83c26217d9ddb04440b /drivers/s390/char/zcore.c | |
| parent | b73104bb79a65ccf3abb8df4e5901b01dbcc829b (diff) | |
| download | linux-db7bc17d33ac1f08d6a9f512eee1a6e13031c968.tar.xz | |
s390/zcore: fix race when reading from hardware system area
[ Upstream commit 9ffed254d938c9e99eb7761c7f739294c84e0367 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/s390/char/zcore.c')
| -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 aaed778f67c4..9748ef463233 100644 --- a/drivers/s390/char/zcore.c +++ b/drivers/s390/char/zcore.c @@ -53,6 +53,7 @@ static struct dentry *zcore_reipl_file; static struct dentry *zcore_hsa_file; static struct ipl_parameter_block *ipl_block; +static DEFINE_MUTEX(hsa_buf_mutex); static char hsa_buf[PAGE_SIZE] __aligned(PAGE_SIZE); /* @@ -69,19 +70,24 @@ 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; } @@ -99,9 +105,11 @@ 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; @@ -111,6 +119,7 @@ int memcpy_hsa_kernel(void *dest, unsigned long src, size_t count) dest += bytes; count -= bytes; } + mutex_unlock(&hsa_buf_mutex); return 0; } |