On pátek 28. července 2023 8:58:16 CEST 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. > > Previous submission is an RFC: [1]. There are no code changes since > then. The RFC prefix is dropped. The Tested-by tag from Laurence is > added. > > There's similar submission from Saurav [2], but we agreed I could nack > it and proceed with my one. > > [1] https://lore.kernel.org/linux-scsi/20230724120241.40495-1-oleksandr@xxxxxxxxxx/ > [2] https://lore.kernel.org/linux-scsi/20230726101236.11922-1-skashyap@xxxxxxxxxxx/ > > 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(-) > > Oops, I forgot to add: Reviewed-by: Laurence Oberman <loberman@xxxxxxxxxx> as per [1]. My ask to the maintainer to add it if the submission is accepted, or let me know if I should do a v2 instead. [1] https://lore.kernel.org/linux-scsi/4f35b02968a18e636e1689c9d52729ef63a438f9.camel@xxxxxxxxxx/ -- Oleksandr Natalenko (post-factum) Principal Software Maintenance Engineer
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