Messages in this thread Patches in this message | | | Date | Thu, 19 Jul 2007 23:33:01 -0400 | From | Reiner Sailer <> | Subject | Re: [PATCH] Memory leak in tpm_ascii_bios_measurements_open() fix. |
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Jesper,
thank you very much for finding this error and for posting a patch proposal. Since Kylene is not online, I am responding. Please see my inlines and an alternative patch proposal below.
Jesper Juhl <jesper.juhl@gmail.com> wrote on 07/18/2007 07:11:54 PM:
> Ehlo, > > Coverity found a memory leak in tpm_ascii_bios_measurements_open(). > > If "read_log(log)" fails, then we may leak 'log' and > 'log->bios_event_log'. > > This patch should fix it, but please double check it. I don't know > this code very well and the patch has only been compile tested. > > > Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com> > --- > > drivers/char/tpm/tpm_bios.c | 11 ++++++++--- > 1 files changed, 8 insertions(+), 3 deletions(-) > > diff --git a/drivers/char/tpm/tpm_bios.c b/drivers/char/tpm/tpm_bios.c > index 4eba32b..4b26ce4 100644 > --- a/drivers/char/tpm/tpm_bios.c > +++ b/drivers/char/tpm/tpm_bios.c > @@ -427,7 +427,7 @@ static int > tpm_ascii_bios_measurements_open(struct inode *inode, > return -ENOMEM; > > if ((err = read_log(log))) > - return err; > + goto out_free;
log->bios_event_log should not be pointing to allocated memory here (seems cleaner if read_log cleans its allocated memory in the error case) ---> just free log
> > /* now register seq file */ > err = seq_open(file, &tpm_ascii_b_measurments_seqops); > @@ -435,10 +435,15 @@ static int > tpm_ascii_bios_measurements_open(struct inode *inode, > seq = file->private_data; > seq->private = log; > } else { > - kfree(log->bios_event_log); > - kfree(log); > + goto out_free; > } > + > +out: > return err; > +out_free: > + kfree(log->bios_event_log); > + kfree(log); > + goto out; > } > const struct file_operations tpm_ascii_bios_measurements_ops = { > >
The following patch should be sufficient to fix the problem you discovered: --- drivers/char/tpm/tpm_bios.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) Index: linux-2.6.22-rc7/drivers/char/tpm/tpm_bios.c =================================================================== --- linux-2.6.22-rc7.orig/drivers/char/tpm/tpm_bios.c +++ linux-2.6.22-rc7/drivers/char/tpm/tpm_bios.c @@ -426,9 +426,10 @@ static int tpm_ascii_bios_measurements_o if (!log) return -ENOMEM; - if ((err = read_log(log))) + if ((err = read_log(log))) { + kfree(log); return err; - + } /* now register seq file */ err = seq_open(file, &tpm_ascii_b_measurments_seqops); if (!err) { Do you agree?
Greetings Reiner
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