oldfitdlm not working (opening/reading .fit files)

[egthomas]

I first ran into this issue several years ago at VT (~2012) and now again at Dartmouth after making a fresh installation of VTRST3.5 from github. Calling the IDL routine OldFitOpen on a .fit file results in a buffer overflow immediately after it loads oldfitdlm, however if you explicitly use the IDL function and not the DLM then everything works normally. Similarly, using the IDL routine to open a .fit file and then trying to use the DLM to read the file (via OldFitRead) fails with a returned value of -1. Can anyone else replicate this issue?

(for reference I'm running IDL Version 8.4 on Ubuntu 14.04.4 LTS)

[pasha-ponomarenko]

Probably later. You might have a chat with Keith in Fairbanks -- he has
played around with re-compiling VTRST3.5.

See you there!

Cheers,
Pasha

On 26/05/2016 12:40 PM, egthomas wrote:

I first ran into this issue several years ago at VT (~2012) and now
again at Dartmouth after making a fresh installation of VTRST3.5 from
github. Calling the IDL routine OldFitOpen on a .fit file results in a
buffer overflow immediately after it loads oldfitdlm, however if you
explicitly use the IDL function and not the DLM then everything works
normally. Similarly, using the IDL routine to open a .fit file and
then trying to use the DLM to read the file (via OldFitRead) fails
with a returned value of -1. Can anyone else replicate this issue?

(for reference I'm running IDL Version 8.4 on Ubuntu 14.04.4 LTS)

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#15

Dr Pavlo (Pasha) Ponomarenko

Professional Research Associate
Institute of Space and Atmospheric Studies
University of Saskatchewan

Mailing address:
Physics building
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CANADA
Phone +1 306 966-6458
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Email pasha.ponomarenko@usask.ca
WWW www.usask.ca/~pasha.ponomarenko

ORCID ID: 0000-0001-8407-0193

 The opposite of skeptic is gullible.

---

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might be wrong.

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of the majority, but to escape finding oneself
in the ranks of the insane.

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[egthomas]

Anyone else have a chance to look at this? I'd like to be able to add .fit compatibility for the IDL gridding without resorting to fittofitacf or circumventing the DLM.

[kkotyk]

I honestly dont know enough about IDL and whats happening with the old fit read routines to be able to fix this in a short amount of time.

[ecbland]

I also just noticed this issue and was able to replicate it exactly as Evan describes. I'm running Linux Mint 18 with IDL 8.5.1.

• Emma

[egthomas]

So after browsing through the log files due to the sim_real compilation error in the other thread, it seems like this particular issue is due to the use of 'strncpy' in OldFitIDLtoFitFp and OldFitFitFpToIDL (Lines 53 and 73 of oldfitdlm.c):

In file included from /usr/include/string.h:640:0,
from oldfitdlm.c:14:
In function ‘strncpy’,
inlined from ‘OldFitIDLToFitFp’ at oldfitdlm.c:53:10:
/usr/include/x86_64-linux-gnu/bits/string3.h:120:3: warning: call to __builtin___strncpy_chk will always overflow destination buffer [enabled by default]
return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest));
^
In function ‘strncpy’,
inlined from ‘OldFitFitFpToIDL’ at oldfitdlm.c:73:10:
/usr/include/x86_64-linux-gnu/bits/string3.h:120:3: warning: call to __builtin___strncpy_chk will always overflow destination buffer [enabled by default]
return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest));
^

[egthomas]

Changing lines 53 and 73 of rst/codebase/superdarn/src.dlm/oldfitdlm.1.7/oldfitdlm.c from

strncpy(fitfp->date,ifitfp->date,80);

to

strncpy(fitfp->date,ifitfp->date,32); (to match the size of the date value in the oldfitfp structure)

takes care of the buffer overflow issue, but nonsense values still creep into the other parameters in that structure when you actually try using the oldfitread dlm in IDL. So more work is needed to get this functional again.