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What is the name of the unpack function in Perl?
Perl unpack Function. Description. This function unpacks the binary string STRING using the format specified in TEMPLATE. Basically reverses the operation of pack, returning the list of packed values according to the supplied format.
Are there any security vulnerabilities in Perl before 5.26.3?
Perl before 5.26.3 has a buffer over-read via a crafted regular expression that triggers disclosure of sensitive information from process memory. Perl before 5.26.3 and 5.28.0 before 5.28.1 has a buffer overflow via a crafted regular expression that triggers invalid write operations.
What causes stack corruption in a Perl program?
Stack corruption occurs when a user-defined function requires a non-trivial amount of memory and the Perl stack gets reallocated. An issue was discovered in the DBI module before 1.632 for Perl. Using many arguments to methods for Callbacks may lead to memory corruption.
Where can I Find buffer overflow in Perl?
A buffer overflow was found in perl-DBI < 1.643 in DBI.xs. A local attacker who is able to supply a string longer than 300 characters could cause an out-of-bounds write, affecting the availability of the service or integrity of data.
How to change the repeat count in pack perldoc?
One can replace a numeric repeat count with a template letter enclosed in brackets to use the packed byte length of the bracketed template for the repeat count. For example, the template x [L] skips as many bytes as in a packed long, and the template “$t X [$t] $t” unpacks twice whatever $t (when variable-expanded) unpacks.
How is the packed length calculated in pack perldoc?
For example, the template x [L] skips as many bytes as in a packed long, and the template “$t X [$t] $t” unpacks twice whatever $t (when variable-expanded) unpacks. If the template in brackets contains alignment commands (such as x! [d] ), its packed length is calculated as if the start of the template had the maximal possible alignment.
When to unpack and when to pack in pack perldoc?
When unpacking, A strips trailing whitespace and nulls, Z strips everything after the first null, and a returns data with no stripping at all. If the value to pack is too long, the result is truncated. If it’s too long and an explicit count is provided, Z packs only $count-1 bytes, followed by a null byte.