pkcs7_get_content_data(9)

💖 pkcs7_get_content_data(9) 💖

ok so this is a page from the Kernel API Manual — section 9, kernel-ville, and it's all about pkcs7_get_content_data. bestie, we're cracking open a PKCS#7 message and grabbing the actual content out of it. let's go 🎀

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✨ SYNOPSIS ✨

int pkcs7_get_content_data (const struct pkcs7_message *pkcs7 , const
void **_data , size_t *_data_len , size_t *_headerlen );

like, four args, returns an int. not scary, i promise 🫶

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🌸 ARGUMENTS 🌸

• pkcs7 — the preparsed PKCS#7 message you wanna access. it's const, so hands off, we're just looking 👀
• _data — the place where a pointer to the data gets returned. you hand over the address, it fills in the pointer. classic out-param behavior, lowkey iconic 💅
• _data_len — the place where the data length gets returned. also an out-param, also doing its thing ✨
• _headerlen — the size of the ASN.1 header that is not included in _data. yes, this matters, keep reading 🧚

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🦋 DESCRIPTION 🦋

okay so the whole point: you get access to the data content of the PKCS#7 message. that's the vibe. 💖

and here's the cute part — the size of the header of the ASN.1 object that contains that data is also provided, via _headerlen. so if you want the entire object and not just the inner data, you can use that header length to adjust *_data and *_data_len accordingly. math girl summer 🔥

warning-ish but make it factual: it returns -ENODATA if the data object was missing from the message. so like… check your return value, bestie 😭 no cap.

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👑 SEE ALSO 👑

• Kernel file ./crypto/asymmetric_keys/pkcs7_parser.c
• pkcs7_free_message(9), pkcs7_parse_message(9)

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and that's the whole page, periodt. this little gem lives under ./crypto/asymmetric_keys and the manual's dated October 2026 — so it's giving future icon energy ⭐💜 mwah, go read the parser file, ily 🎀