v2: improved patch description
In Aug 2018 NeilBrown noticed
commit 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface")
"Some ->next functions do not increment *pos when they return NULL...
Note that such ->next functions are buggy and should be fixed.
A simple demonstration is
dd if=/proc/swaps bs=1000 skip=1
Choose any block size larger than the size of /proc/swaps. This will
always show the whole last line of /proc/swaps"
Described problem is still actual. If you make lseek into middle of last output line
following read will output end of last line and whole last line once again.
$ dd if=/proc/swaps bs=1 # usual output
Filename Type Size Used Priority
/dev/dm-0 partition 4194812 97536 -2
104+0 records in
104+0 records out
104 bytes copied
$ dd if=/proc/swaps bs=40 skip=1 # last line was generated twice
dd: /proc/swaps: cannot skip to specified offset
v/dm-0 partition 4194812 97536 -2
/dev/dm-0 partition 4194812 97536 -2
3+1 records in
3+1 records out
131 bytes copied
There are lot of other affected files, I've found 30+ including
/proc/net/ip_tables_matches and /proc/sysvipc/*
This patch-set fixes files related to tpm driver:
/sys/kernel/security/tpm0/ascii_bios_measurements
/sys/kernel/security/tpm0/binary_bios_measurements
https://bugzilla.kernel.org/show_bug.cgi?id=206283
Vasily Averin (2):
tpm: tpm1_bios_measurements_next should increase position index
tpm: tpm2_bios_measurements_next should increase position index
drivers/char/tpm/eventlog/tpm1.c | 2 +-
drivers/char/tpm/eventlog/tpm2.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
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1.8.3.1
