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Fix cymbol command on Ubuntu 18.04 #1399

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disconnect3d opened this issue Nov 30, 2022 · 1 comment
Closed

Fix cymbol command on Ubuntu 18.04 #1399

disconnect3d opened this issue Nov 30, 2022 · 1 comment
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bug testing
Milestone
2022.12

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@disconnect3d
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disconnect3d commented Nov 30, 2022 •
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There's a cymbol test that fails on the Ubuntu 18.04 CI, this issue is there to track it
@gsingh93 gsingh93 added this to the November Release milestone Dec 3, 2022
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The cymbol functionality does not work on old GDB versions because the add-symbol-file command has different interface in old GDBs: it requires an address argument, while in newer GDBs its optional.

This can be seen below.

Older GDB versions:

pwndbg> help add-symbol-file
Load symbols from FILE, assuming FILE has been dynamically loaded.
Usage: add-symbol-file FILE ADDR [-readnow | -readnever | -s SECT-NAME SECT-ADDR]...
ADDR is the starting address of the file's text.
Each '-s' argument provides a section name and address, and
should be specified if the data and bss segments are not contiguous
with the text.  SECT-NAME is a section name to be loaded at SECT-ADDR.
The '-readnow' option will cause GDB to read the entire symbol file
immediately.  This makes the command slower, but may make future operations
faster.
The '-readnever' option will prevent GDB from reading the symbol file's
symbolic debug information.
pwndbg> version
Gdb:      8.1.1
Python:   3.6.9 (default, Jun 29 2022, 11:45:57)  [GCC 8.4.0]
Pwndbg:   1.1.1 build: c5d8800
Capstone: 4.0.1024
Unicorn:  2.0.7

Newer GDB versions:

pwndbg> help add-symbol-file
Load symbols from FILE, assuming FILE has been dynamically loaded.
Usage: add-symbol-file FILE [-readnow | -readnever] [-o OFF] [ADDR] [-s SECT-NAME SECT-ADDR]...
ADDR is the starting address of the file's text.
Each '-s' argument provides a section name and address, and
should be specified if the data and bss segments are not contiguous
with the text.  SECT-NAME is a section name to be loaded at SECT-ADDR.
OFF is an optional offset which is added to the default load addresses
of all sections for which no other address was specified.
The '-readnow' option will cause GDB to read the entire symbol file
immediately.  This makes the command slower, but may make future operations
faster.
The '-readnever' option will prevent GDB from reading the symbol file's
symbolic debug information.
pwndbg> version
Gdb:      12.1
Python:   3.10.6 (main, Nov  2 2022, 18:53:38) [GCC 11.3.0]
Pwndbg:   1.1.1 build: c5d8800
Capstone: 4.0.1024
Unicorn:  2.0.0
pwndbg>

@disconnect3d disconnect3d changed the title Fix CI: cymbol test Fix cymbol on Ubuntu 18.04 Dec 3, 2022
@disconnect3d disconnect3d changed the title Fix cymbol on Ubuntu 18.04 Fix cymbol command on Ubuntu 18.04 Dec 3, 2022
disconnect3d added a commit that referenced this issue Dec 3, 2022
@disconnect3d
Fix #1399: cymbol command on old GDB
2cda657 
The cymbol command did not work on old GDB versions like 8.2 because
they require the ADDR argument to be passed into the `add-symbol-file`
command unlike newer GDB versions in which the argument is optional.

This can be seen below.

```
pwndbg> help add-symbol-file
Load symbols from FILE, assuming FILE has been dynamically loaded.
Usage: add-symbol-file FILE ADDR [-readnow | -readnever | -s SECT-NAME SECT-ADDR]...
ADDR is the starting address of the file's text.
Each '-s' argument provides a section name and address, and
should be specified if the data and bss segments are not contiguous
with the text.  SECT-NAME is a section name to be loaded at SECT-ADDR.
The '-readnow' option will cause GDB to read the entire symbol file
immediately.  This makes the command slower, but may make future operations
faster.
The '-readnever' option will prevent GDB from reading the symbol file's
symbolic debug information.
pwndbg> version
Gdb:      8.1.1
Python:   3.6.9 (default, Jun 29 2022, 11:45:57)  [GCC 8.4.0]
Pwndbg:   1.1.1 build: c5d8800
Capstone: 4.0.1024
Unicorn:  2.0.7
```

vs

```
pwndbg> help add-symbol-file
Load symbols from FILE, assuming FILE has been dynamically loaded.
Usage: add-symbol-file FILE [-readnow | -readnever] [-o OFF] [ADDR] [-s SECT-NAME SECT-ADDR]...
ADDR is the starting address of the file's text.
Each '-s' argument provides a section name and address, and
should be specified if the data and bss segments are not contiguous
with the text.  SECT-NAME is a section name to be loaded at SECT-ADDR.
OFF is an optional offset which is added to the default load addresses
of all sections for which no other address was specified.
The '-readnow' option will cause GDB to read the entire symbol file
immediately.  This makes the command slower, but may make future operations
faster.
The '-readnever' option will prevent GDB from reading the symbol file's
symbolic debug information.
pwndbg> version
Gdb:      12.1
Python:   3.10.6 (main, Nov  2 2022, 18:53:38) [GCC 11.3.0]
Pwndbg:   1.1.1 build: c5d8800
Capstone: 4.0.1024
Unicorn:  2.0.0
pwndbg>
```
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bug testing
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2022.12
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@gsingh93 @disconnect3d