| Message ID | 20241227230940.20894-1-v.shevtsov@maxima.ru (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | IB/hfi1: fix buffer underflow in fault injection code | expand |
diff --git a/drivers/infiniband/hw/hfi1/fault.c b/drivers/infiniband/hw/hfi1/fault.c index ec9ee59fcf0c..2d87f9c8b89d 100644 --- a/drivers/infiniband/hw/hfi1/fault.c +++ b/drivers/infiniband/hw/hfi1/fault.c @@ -190,7 +190,8 @@ static ssize_t fault_opcodes_read(struct file *file, char __user *buf, bit = find_next_bit(fault->opcodes, bitsize, zero); } debugfs_file_put(file->f_path.dentry); - data[size - 1] = '\n'; + if (size) + data[size - 1] = '\n'; data[size] = '\0'; ret = simple_read_from_buffer(buf, len, pos, data, size); free_data:
[Why] The fault injection code may have a buffer underflow, which may cause memory corruption by writing a newline character before the base address of the array. This can happen if the fault->opcodes bitmap is empty. Since a file in debugfs is created with an empty bitmap, it is possible to read the file before any set bits are written to it. [How] Fix this by checking that the size variable is greater than zero, otherwise return zero as the number of bytes read. Found by Linux Verification Center (linuxtesting.org) with Svace. Fixes: a74d5307caba ("IB/hfi1: Rework fault injection machinery") Signed-off-by: Vitaliy Shevtsov <v.shevtsov@maxima.ru> --- drivers/infiniband/hw/hfi1/fault.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)