Memory buffer used for reading out data from hardware system
area is not protected against concurrent access.
Reported-by: Matthew Wilcox <[email protected]>
Fixes: 411ed3225733 ("[S390] zfcpdump support.")
Signed-off-by: Alexander Gordeev <[email protected]>
---
drivers/s390/char/zcore.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
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;
}
--
2.34.1