On Mon, 2023-07-24 at 14:02 +0200, Oleksandr Natalenko wrote: > qedf driver, debugfs part of it specifically, touches __user pointers > directly for printing out info to userspace via sprintf(), which may > cause crash like this: > > BUG: unable to handle kernel paging request at 00007ffd1d6b43a0 > IP: [<ffffffffaa7a882a>] string.isra.7+0x6a/0xf0 > Oops: 0003 [#1] SMP > Call Trace: > [<ffffffffaa7a9f31>] vsnprintf+0x201/0x6a0 > [<ffffffffaa7aa556>] sprintf+0x56/0x80 > [<ffffffffc04227ed>] qedf_dbg_stop_io_on_error_cmd_read+0x6d/0x90 > [qedf] > [<ffffffffaa65bb2f>] vfs_read+0x9f/0x170 > [<ffffffffaa65cb82>] SyS_pread64+0x92/0xc0 > > Avoid this by preparing the info in a kernel buffer first, either > allocated on stack for small printouts, or via vmalloc() for big > ones, > and then copying it to the userspace properly. > > I'm not sure how big the vmalloc()'ed buffer should be, and also > whether > vmalloc()'ing it directly in the _read() function is a good idea, > hence > RFC prefix. > > The qedf_dbg_stop_io_on_error_cmd_read()-related patch is actually > tested, > the rest is compile-tested only. > > Oleksandr Natalenko (3): > scsi: qedf: do not touch __user pointer in > qedf_dbg_stop_io_on_error_cmd_read() directly > scsi: qedf: do not touch __user pointer in > qedf_dbg_debug_cmd_read() > directly > scsi: qedf: do not touch __user pointer in > qedf_dbg_fp_int_cmd_read() > directly > > drivers/scsi/qedf/qedf_dbg.h | 2 ++ > drivers/scsi/qedf/qedf_debugfs.c | 35 +++++++++++++++++++----------- > -- > 2 files changed, 23 insertions(+), 14 deletions(-) > > -- > 2.41.0 > I will test the series, the one patch was already tested. This was reproduced in our LAB Will report back after testing Regards Laurence
